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Power of powers - class-X

Attempted 0/94 Correct 0 Score 0

Simplify: $( 16x ^{16} )^{\dfrac{3}{4}}$

  1. $8 x^{16}$

  2. $2 x^{12}$

  3. $8 x^{12}$

  4. $2 x^{16}$


Correct Option: C
Explanation:
${\left( 16{x}^{16} \right)}^{\cfrac{3}{4}} = {\left( {2}^{4} {x}^{16} \right)}^{\cfrac{3}{4}}$
$\Rightarrow \; = {\left( {2}^{4} \right)}^{\cfrac{3}{4}} {\left( {x}^{16} \right)}^{\cfrac{3}{4}}$

$\Rightarrow \; = {2}^\left( {4 \times \cfrac{3}{4}} \right)  {x}^\left({16 \times \cfrac{3}{4}} \right)$

$\Rightarrow \; = {2}^{3} \times {x}^{12}$

$\Rightarrow \; = 8{x}^{12}$

The value of $(0.243)^{0.2}\times (10)^{0.6}$ is 

  1. $3$

  2. $9$

  3. $0.3$

  4. None of these


Correct Option: A
Explanation:

Now,

$(0.243)^{0.2}\times (10)^{0.6}$
$=\left(\dfrac{243}{1000}\right)^{\dfrac{1}{5}}\times (10)^{\dfrac{3}{5}}$
$=\left(\dfrac{3^5}{10^3}\right)^{\dfrac{1}{5}}\times (10)^{\dfrac{3}{5}}$
$=3\times (10)^{-\dfrac{3}{5}+\dfrac{3}{5}}$
$=3$.

Find the value of ${(6561)^{0.25}}$

  1. $3$

  2. $7$

  3. $9$

  4. $19$


Correct Option: C
Explanation:

$ \Rightarrow 6561 = {3^8}$

${\left( {6561} \right)^{0.25}} = {\left( {6561} \right)^{1/4}}$

$ = {\left( {{3^8}} \right)^{1/4}}$

$ = {\left( 3 \right)^{8/4}}$

$ = {3^2} = 9$

Solve:

$x^{\sqrt{x}}=\sqrt{x^x}$.

  1. $2$

  2. $3$

  3. $4$

  4. none of these


Correct Option: C
Explanation:

Given,

$x^{\sqrt{x}}=\sqrt{x^x}$
or, $x^{\sqrt{x}}={x^\dfrac{x}{2}}$
or, $\sqrt{x}=\dfrac{x}{2}$
Squaring both sides we get,
$x=\dfrac{x^2}{4}$
Since $x\ne 0$ so $x=4$.

The difference between $3^{3^3}$ and $(3^3)^3$

  1. $3^{27}-3^9$

  2. $0$

  3. $27^3-3^{27}$

  4. $3^{18}(3^9-1)$


Correct Option: A
Explanation:

We have,

$3^{3^3}=3^{(3^3)}=3^{27}$ and $(3^3)^3=(3^{3\times 3})=3^9$.
So the difference between them is $3^{27}-3^9$.

${\left( { - 2} \right)^{ - 5}}{\left( { - 2} \right)^6}$ is equals to

  1. $2$

  2. $-2$

  3. $-5$

  4. $6$


Correct Option: B
Explanation:

Given that:

$(-2)^{-5}(-2)^{6}$
$=(\dfrac{-1}{2})^{5}(-2)^{6}$
$=(\dfrac{-1}{32})({64})$
$=(-1)(2)$
$=(-2)$

Hence, the value $-2$.

If $x = {y^{\frac{1}{a}}},\,y = {z^{\frac{1}{b}}}\,\,{\text{and}}\,\,z = {x^{\frac{1}{c}}}\,{\text{where}}\,x \ne 1,y \ne 1,\,z \ne 1$, then what is the value of $abc$?

  1. $-1$

  2. $1$

  3. $0$

  4. $3$


Correct Option: B
Explanation:

Given $x=y^{\dfrac{1}{a}}.....(1)$

$y=z^{\dfrac{1}{b}}.....(2)$
$z=x^{\dfrac{1}{c}}.....(3)$
Putting the value of y from equation (2) in equation (1)
$x=[(z)^{\dfrac{1}{b}}]^{\dfrac{1}{a}}\Rightarrow x=z^{\dfrac{1}{ab}}$
Putting the value of z from equation (3) in the above equation
$x=[(x)^{\dfrac{1}{c}}]^{\dfrac{1}{ab}}\Rightarrow x^1=x^{\dfrac{1}{abc}}$
$\therefore\dfrac{1}{abc}=1\Rightarrow abc=1$

The value of $\frac{{{{100}^{98}} + {{100}^{100}}}}{{{{100}^{98}}}} + 1$ is equal to_____

  1. 10001

  2. 10002

  3. 1001

  4. 1002


Correct Option: B
Explanation:

The value of

  $ \dfrac{{{100}^{98}}+{{100}^{100}}}{{{100}^{98}}}+1 $

 $ =\dfrac{{{100}^{98}}}{{{100}^{98}}}+\dfrac{{{100}^{100}}}{{{100}^{98}}}+1 $

 $ =1+{{100}^{100-98}}+1 $

 $ ={{100}^{2}}+2 $

 $ =10000+2 $

 $ =10002 $


Hence, this is the answer. 

option (B) is correct.

Simplify the following $(3r^2)\times (9r^2)^{3/2} \div (27r^{-3})^{1/3}$ and find the power of $r$.

  1. $5$

  2. $2$

  3. $7$

  4. $6$


Correct Option: D
Explanation:

We have,
$(3r^2)\times (9r^2)^{3/2}\div(27r^{-3})^{1/3}\$

$\Rightarrow (3r^2)\times ((3r)^2)^{3/2}\div(3^3r^{-3})^{1/3}\$
$\Rightarrow (3r^2)\times (3r)^{3}\div(3r^{-1})\$

$\Rightarrow (3r^2)\times (3^3r^3)\times(3^{-1}r)\\$
$\Rightarrow 27r^6$

So, the power of $r$ is $6$.

Hence, this is the answer.

The value of $\dfrac { { 2 }^{ m+3 }\times { 3 }^{ 2m-n }\times { 5 }^{ m+n+3 }\times { 6 }^{ n+1 } }{ { 6 }^{ m+1 }\times { 10 }^{ n+3 }\times { 15 }^{ m } } $ is equal to 

  1. $0$

  2. $1$

  3. $2^ {m}$

  4. $none\ of\ these$


Correct Option: B
Explanation:

Now,

$\dfrac { { 2 }^{ m+3 }\times { 3 }^{ 2m-n }\times { 5 }^{ m+n+3 }\times { 6 }^{ n+1 } }{ { 6 }^{ m+1 }\times { 10 }^{ n+3 }\times { 15 }^{ m } } $ 
$=\dfrac { { 2 }^{ m+3 }\times { 3 }^{ 2m-n }\times { 5 }^{ m+n+3 }\times(2^{n+1}\times { 3 }^{ n+1 }) }{ (2^{m+1}\times { 3 }^{ m+1 })\times (2^{n+3}\times { 5 }^{ n+3 })\times (3^{m}\times { 5 }^{ m }) } $ 
$=\dfrac { { 2 }^{ m+n+4 }\times { 3 }^{ 2m+1 }\times { 5 }^{ m+n+3 } }{ { 2 }^{ m+n+4 }\times { 3 }^{ 2m+1 }\times { 5 }^{ mm+n+3 } } $ 
$=1$.

The value of $\displaystyle (512)^{\tfrac{-2}{9}}$ is:

  1. $\displaystyle \frac{1}{2}$

  2. $2$

  3. $4$

  4. $\displaystyle \frac{1}{4}$


Correct Option: D
Explanation:

$\displaystyle \left ( 512 \right )^{\frac{-2}{9}}=\left ( 2^{9} \right )^{\frac{-2}{9}}=2^{-2}=\frac{1}{4}$

$8^3 \times 8^2 \times 8^{-5}$ is equal to ?

  1. $0$

  2. $1$

  3. $8$

  4. $64$


Correct Option: B
Explanation:

$={8}^{3+2-5}$

$={8}^{0}$
$={1}$

The largest number among the following is

  1. $\displaystyle 3^{2^{2^{2^2}}}$

  2. $\displaystyle \left { \left ( 3^{2} \right )^{2} \right }^{2}$

  3. $\displaystyle 3^{2}\times 3^{2}\times 3^{2}$

  4. $3222$


Correct Option: A
Explanation:

$1) 3^{2^{2^{2^{2}}}}=3^{2^{2^{4}}}=3^{16}$


$ 2) \left { \left ( 3^{2} \right )^{2} \right }^{2}=3^{8}=6561$

$ 3) 3^{2}\times 3^{2}\times 3^{2}=3^{2+2+2}=3^{6}=729$

$ \therefore 3^{2^{2^{2^{2}}}}>\left { \left ( 3^{2} \right )^{2} \right }^{2}>3222>3^{2}\times 3^{2}\times 3^{2}$

The largest number among the above is $3^{2^{2^{2^{2}}}}$.

If $4^{2x}=\frac {1}{32}$, then the value of x is

  1. $\frac {5}{4}$

  2. $-\frac {5}{4}$

  3. $\frac {3}{4}$

  4. $-\frac {5}{2}$


Correct Option: B
Explanation:

$4^{2x}=\frac {1}{32}\Rightarrow (2^2)^{2x}=\frac {1}{2^5}$
$\Rightarrow 2^{4x}=2^{-5}$
$\Rightarrow 4x=-5$
$x=\frac {-5}{4}$

$ \displaystyle x^{m}=x^{n}\Rightarrow m =  $

  1. $>n$

  2. $=n$

  3. $<n$

  4. None of this


Correct Option: B
Explanation:

Given that:

$x^m=x^n$
$\because$ bases are equal in both sides, 
$\therefore$ on comparing the powers, we have
$\Rightarrow m=n$.

The number of digits in the number $N=2^{12}\times5^8$ is

  1. $9$

  2. $10$

  3. $11$

  4. $20$


Correct Option: B
Explanation:

The factors $2$ and $5$ in the given number are the factors of $10$.
We can write $N$ as-
$ N=2^8\times2^4\times5^8 $
$=2^4(2^8\times5^8)$
$=2^4(10)^8=16\times10^8$
Therefore, the number of digits in $N$ is $10$.

The value of $x^{4/8} \div x^{12/8}$---

  1. $x^{4/8}$

  2. $x^{6}$

  3. $\displaystyle \frac{1}{x}$

  4. $x$


Correct Option: C
Explanation:

$x^1/2 / x^3/2$


$=x^(1/2-3/2)$

$=x^{-1}$

$=\dfrac{1}{x}$

Evaluate : $\displaystyle \left( \frac{3}{4} \right)^0 \times 2 \frac{1}{4} - \left( 2 \frac{1}{4} \right)^0 \times \frac{3}{4}$--

  1. $\displaystyle \frac{3}{2}$

  2. $\displaystyle \frac{3}{4}$

  3. $1$

  4. $\displaystyle 2\frac{1}{4}$


Correct Option: A
Explanation:

$1 \times \dfrac{9}{4} - 1 \times \dfrac{3}{4}$

$=\dfrac{9}{4} - \dfrac{3}{4}$

$=\dfrac{6}{4}$

$=\dfrac{3}{2}$

Find the value of $2 \times 256^{3/4}$---

  1. $128$

  2. $\displaystyle \frac{1}{128}$

  3. $-128$

  4. $\displaystyle - \frac{1}{128}$


Correct Option: A
Explanation:

correct option is A..

The value of $x^{5/6} \div x^{11/6}$---

  1. $\displaystyle \frac{1}{x}$

  2. $x^{1/6}$

  3. $x^6$

  4. $16$


Correct Option: A
Explanation:

$=\dfrac {x^{5/6}}{x^{11/6}}$

$=x^{5/6-11/6}$
$=x^{-1}$
$=\dfrac 1x$

Which of the following expresses the power of quotient rule?

  1. $\left (\dfrac {a}{b}\right )^{m} = \dfrac {a^{m}}{b^{m}}$

  2. $\left (\dfrac {a}{b}\right )^{m} = \left (\dfrac {a}{b}\right )^{m}$

  3. $\left (\dfrac {a}{b}\right )^{m} = \dfrac {a^{m}}{b}$

  4. $\left (\dfrac {a}{b}\right )^{m} = \dfrac {a^{m}}{b^{-m}}$


Correct Option: A
Explanation:

If the division of two bases is powered by the same exponent,

 then the result is division of both the bases, 
each powered by the given exponent.
$\therefore \left (\dfrac {a}{b}\right )^{m} = \dfrac {a^{m}}{b^{m}}$
So, option $A$ is correct.

Which of the following represents the power of product rule?

  1. $(x\times y)^{a} = x^{a} \times y$

  2. $(x\times y)^{a} = x \times y^{a}$

  3. $(x\times y)^{a} = x^{a} + y^{a}$

  4. $(x\times y)^{a} = x^{a} \times y^{a}$


Correct Option: D
Explanation:

If the product of the bases is powered  by the same exponent, 

then the result is multiplication of all the bases, 
each powered by the given exponent.
$\therefore (x\times y)^{a} = x^{a} \times y^{a}$.
So, option $D$ is correct.

Evaluate: $\left (\dfrac {2^{3}}{3^{3}} \right )^{2}$

  1. $\dfrac {64}{729}$

  2. $\dfrac {729}{64}$

  3. $\dfrac {32}{243}$

  4. $\dfrac {243}{32}$


Correct Option: A
Explanation:

$\left (\dfrac {2^{3}}{3^{3}} \right )^{2} = \dfrac {2^{6}}{3^{6}} = \dfrac {64}{729}$


So, option $A$ is correct.

On simplifying  $\displaystyle 3^{3}\times a^{3}\times b^{3}$, we get

  1. $\displaystyle \left ( 3ab \right )^{3} $

  2. $\displaystyle 3\left ( ab \right )^{3} $

  3. $\displaystyle \left ( 27ab \right )^{3} $

  4. None of these


Correct Option: A
Explanation:

$\displaystyle 3^{2}\times a^{3}\times b^{3}=\left ( 3ab \right )^{3}$.

This is the power of product law of exponents.
So, option $A$ is correct.

Find the value of: $\displaystyle \left [ \left ( -1 \right )^{2}\times \left ( -1 \right )^{3}\times \left ( -1 \right )^{4} \right ]^{6}$

  1. $3$

  2. $-1$

  3. $1$

  4. $\displaystyle 3^{6}$


Correct Option: C
Explanation:

$\displaystyle \left [ \left ( -1 \right )^{2}\times \left ( -1 \right )^{3}\times \left ( -1 \right )^{4} \right ]^{6}$

=$\displaystyle \left [ \left ( -1 \right )^{12}\times \left ( -1 \right )^{18}\times \left ( -1 \right )^{24} \right ]$

=$\displaystyle \left [ 1\times 1\times 1 \right ]$ =$1$
So, option $C$ is correct.

The value of $\displaystyle \left (-4  \right ) ^{3}\times \left ( -3 \right )^{3}$ is _____?

  1. $\displaystyle 12^{3}$

  2. $\displaystyle -12^{3}$

  3. $\displaystyle -7^{3}$

  4. $\displaystyle 7^{3}$


Correct Option: A
Explanation:

$\displaystyle \left ( -4 \right )^{3}\times \left ( -3 \right )^{3}=\left ( -4\times -3 \right )^{3}$

$=\displaystyle \left ( -4\times -3 \right )^{3}$
$=\displaystyle 12^3$

Find the expression which equals $\displaystyle a^{x}\times b^{x}$.

  1. $\left [\displaystyle a^{x}+ b^{x} \right ]$

  2. $\displaystyle \left ( ab\right )^x $

  3. $\displaystyle \left (a+b \right )^{x} $

  4. $\displaystyle a\left ( b \right )^{x} $


Correct Option: B
Explanation:

$\displaystyle a^{x}\times b^{x}=\left ( ab \right )^{n}$

So, option $B$ is correct.

Evaluate: $\displaystyle 5^{2}\times 3^{2} $

  1. $\displaystyle \left (53 \right ) ^{2}$

  2. $\displaystyle \left (15 \right ) ^{2}$

  3. $\displaystyle \left (8 \right ) ^{2}$

  4. $60$


Correct Option: B
Explanation:

$\displaystyle 5^{2}\times 3^{2}=\left ( 15 \right )^{2}$

So, option $B$ is correct.

Evaluate: $\displaystyle \left [ \left ( 4 \right )^{\tfrac{1}{4}}\times \left ( 2 \right )^{\tfrac{1}{2}}\times \left ( 5 \right )^{\tfrac{1}{5}} \right ]^{0}$

  1. $40$

  2. $0$

  3. $1$

  4. $10$


Correct Option: C
Explanation:

=$\displaystyle \left [ \left ( 4 \right )^{\tfrac{1}{4}}\times \left ( 2 \right )^{\tfrac{1}{2}} \times \left ( 5 \right )^{\tfrac{1}{2}}\right ]^{0}$

=$\displaystyle 4^{0}\times 2^{0}\times 5^{0}$
=$\displaystyle 1\times 1\times 1$
=$1$
So, option $C$ is correct.

The value of $\displaystyle \left [ \left ( \frac{-2}{5} \right )^{3} \right ]^{2}$ is:

  1. $\displaystyle -\frac{2}{5}$

  2. $\displaystyle -\frac{32}{3125}$

  3. $\displaystyle\frac{64}{15625}$

  4. $\displaystyle -\frac{64}{15625}$


Correct Option: C
Explanation:

$\displaystyle \left [ \left ( \frac{-2}{5} \right )^{3} \right ]^{2}=\left ( \frac{-2}{5} \right )^{6}=\frac{\left ( -2 \right )^{6}}{5^{6}}=\frac{64}{15625}$

Hence, option $C$ is correct.

Simplify: $\displaystyle \left ( -a \right )^{9}\times \left ( -b \right )^{9}$ 

  1. $\displaystyle \left ( ab \right )^{9}$

  2. $\displaystyle \left ( -ab \right )^{9}$

  3. $\displaystyle -\left ( ab \right )^{9}$

  4. $\displaystyle \left ( a-b \right )^{9}$


Correct Option: A
Explanation:

$(-a)^9 \times (-b)^9 = [ -a \times -b]^9$


= $ [ a \times b]^9$

=$ (ab)^9$
So, option $A$ is correct.

Evaluate $\displaystyle\left [ \left ( \frac{-3}{7} \right )^{-1} \right ]^{2}$

  1. $\displaystyle\left ( \frac{-9}{49} \right )$

  2. $\displaystyle\left ( \frac{9}{49} \right )$

  3. $\displaystyle\left ( \frac{-49}{9} \right )$

  4. $\displaystyle\left ( \frac{49}{9} \right )$


Correct Option: D
Explanation:

$\displaystyle\left [ \frac{-3}{7} ^{-1}\right ]^{2}=\left [ \left ( \frac{-7}{3} \right )^{1} \right ]^{2}=\left ( \frac{-7}{3} \right )^{2}=\frac{49}{9}$

Hence, option $D$ is correct.

The value of $\displaystyle \left ( \frac{2}{3}\right )^{-5}$ is:

  1. $\displaystyle -\frac{32}{243}$

  2. $\displaystyle \frac{32}{243}$

  3. $\displaystyle -\frac{243}{32}$

  4. $\displaystyle \frac{243}{32}$


Correct Option: D
Explanation:

$\displaystyle\left ( \frac{2}{3} \right )^{-5}=\left ( \frac{3}{2} \right )^{5}=\frac{3^{5}}{2^{5}}=\frac{243}{32}$

Hence, option $D$ is correct.

$\displaystyle \left ( 16\div 15 \right )^{3}$ can also be expressed as:

  1. $\displaystyle 16^{3}\div 15^{3} $

  2. $\displaystyle 16^{3}\div 15 $

  3. $\displaystyle 16\div 15^{3} $

  4. $\displaystyle 15^{3}\div 16^{3} $


Correct Option: A
Explanation:

$\displaystyle\left ( 16\div 15 \right )^{3}=16^{3}\div 15^{3}$ 


This is quotient law of exponents.
Hence, option $A$ is correct

Which of the law does not stand true ?

  1. $\displaystyle \frac{a^{m}}{a^{n}}=a^{m-n}$

  2. $\displaystyle \left ( \frac{a^{m}}{a^{n}} \right )^{x}=\frac{a^{mx}}{a^{nx}}$

  3. $\displaystyle \frac{a^{m}}{b^{m}}=\left ( \frac{a}{b} \right )^{m}$

  4. $\displaystyle \frac{a^{m}}{a^{m}}=a^{m}$


Correct Option: D
Explanation:

$\displaystyle \frac{a^{m}}{a^{m}}=1$
$\displaystyle\therefore  \frac{a^{m}}{a^{m}}\neq a^{m}$

Which of the following expressions is equivalent to $x^3x^5$?

  1. $2x^8$

  2. $x^{15}$

  3. $x^2$

  4. $x^8$

  5. $2x^{15}$


Correct Option: D
Explanation:

We know, $x^a \times x^b=x^{(a+b)}$
Therefore the value of ${x}^{3}{x}^{5} = {x}^{3+5} = {x}^{8}$

A number when divided by $296$ leaves $75$ as remainder. When the same number is divided by $37$, the remainder will be:

  1. $1$

  2. $2$

  3. $8$

  4. $11$


Correct Option: A
Explanation:

Let $x=296q+75$
$=(37\times 8q+37\times 2)+1$
$=37(8q+2)+1$
Thus, when the number is divided by $37$, the remainder is $1$.

$n$ is a whole number which when divided by $4$ given $3$ as remainder. What will be the remainder when $2n$ is divided by $4$?

  1. $3$

  2. $2$

  3. $1$

  4. $0$


Correct Option: B
Explanation:

Let $n=4q+3$. Then $2n=8q+6=4(2q+1)+2$
Thus, when $2n$ is divided by $4$, the remainder is $2$.

$\dfrac{1}{1+x^{(b-a)}+x^{(c-a)}}+\dfrac{1}{1+x^{(a-b)}+x^{(c-b)}}+\dfrac{1}{1+x^{(b-c)}+x^{(a-c)}} = ?$

  1. $0$

  2. $1$

  3. $x^{a-b-c}$

  4. None of these


Correct Option: B
Explanation:

Given Exp. = $\dfrac{1}{\begin{pmatrix}1+\dfrac{x^b}{x^a}+\dfrac{x^c}{x^a}\end{pmatrix}} + \dfrac{1}{\begin{pmatrix}1+\dfrac{x^a}{x^b}+\dfrac{x^c}{x^b}\end{pmatrix}} + \dfrac{1}{\begin{pmatrix}1+\dfrac{x^b}{x^c}+\dfrac{x^a}{x^c}\end{pmatrix}}$
$= \dfrac{x^a}{(x^a+x^b+x^c)}+\dfrac{x^b}{(x^a+x^b+x^c)} + \dfrac{x^c}{(x^a+x^b+x^c)}$
$= \dfrac{x^a+x^b+x^c}{(x^a+x^b+x^c)}$
$= 1.$

The value of $[(10)^{150}\div (10)^{146}]$

  1. $1000$

  2. $10000$

  3. $100000$

  4. $10^6$


Correct Option: B
Explanation:

$(10)^{150}\div (10)^{146} = \dfrac{10^{150}}{10^{146}}$
$= 10^{150-146}$
$= 10^4$
$= 10000.$

$(256)^{0.16}\times (256)^{0.09} = ?$

  1. 4

  2. 16

  3. 64

  4. 256.25


Correct Option: A
Explanation:

$(256)^{0.16}\times (256)^{0.09} = (256)^{(0.16+0.09)}$
$= (256)^{0.25}$
$= (256)^{(25/100)}$
$= (256)^{(1/4)}$
$= (4^4)^{(1/4)}$
$= 4^{4(1/4)}$
$= 4^1$
$= 4$

Simplify and give reasons:
${ \left( \cfrac { 1 }{ 2 }  \right)  }^{ -3 }\times { \left( \cfrac { 1 }{ 4 }  \right)  }^{ -3 }\times { \left( \cfrac { 1 }{ 5 }  \right)  }^{ -3 }\quad $

  1. ${40}^{3}$

  2. ${40}^{-3}$

  3. ${40}^{6}$

  4. None of these


Correct Option: A
Explanation:

we know,

$(\dfrac{a}{b})^{-m}=(\dfrac{b}{a})^{m}$
So,
$(\dfrac{1}{2})^{-3}=(\dfrac{2}{1})^{3}=2^{3}$

$(\dfrac{4}{1})^{-3}=(\dfrac{4}{1})^{3}=4^{3}$

$(\dfrac{5}{1})^{-3}=(\dfrac{5}{1})^{3}=5^{3}$
now we know,

\$a^{m}b^{m}*c^{m}=(abc)^{m}$

$\implies(2)^{3}(4)^{3}*(5)^{3}$

$=(40)^{3}$

$(-2)^{-5}\times (-2)^{6}$ is equal to

  1. $-2$

  2. $2$

  3. $-5$

  4. $6$


Correct Option: A
Explanation:

As we know that $a^{m}\times a^{n}=a^{(m+n)}$


 So, $(-2)^{-5}\times (-2)+^{6}=(-2)^{-5+6}$ 

        $(-2)^{-5}\times (-2)+^{6}=(-2)^{1}$ 

        $(-2)^{-5}\times (-2)+^{6}=-2$

$(-1)^{50}$ is equal to

  1. $-1$

  2. $50$

  3. $-50$

  4. $1$


Correct Option: D
Explanation:

As we can see that the power is even and we know that when $(-1)$ is raised to some odd power then its value remains same i.e. $-1$ but when the power is even its sign is changed i.e. $1$ . therefore, $(-1)^{50}=1$

$(-2)^{-2}$ is equal to

  1. $\dfrac {1}{2}$

  2. $\dfrac {1}{4}$

  3. $\dfrac {-1}{2}$

  4. $\dfrac {-1}{4}$


Correct Option: B
Explanation:
 As we know that $a^{-b}$ is equal to $1/a^{b}.$ So, $(-2)^{-2}$ is equal to $1/(-2)^{2}$.
 
 Also,we know that $(-2)^{2}=(-2)\times (-2)=4$ 

 Therefore , $(-2)^{-2}=1/4$

Choose the correct option:
$\left[\dfrac{{100}}{{101}}\right]^3$

  1. $\dfrac{{100}^3}{{101}^3}$

  2. $\dfrac{{100}^4}{{101}^4}$

  3. $\dfrac{{1000}^2}{{101}^2}$

  4. $\dfrac{{100}}{{101}}$


Correct Option: A
Explanation:

$Now\quad \left[ \dfrac { 100 }{ 101 }  \right] ^{ 3 }\quad \ \quad \quad =\quad \dfrac { { 10 }0^{ 3 } }{ 101^{ 3 } } \quad \left( \because \left( \dfrac { { a }^{ m } }{ { b }^{ m } }  \right) =\left( \dfrac { a }{ b }  \right) ^{ m } \right) \ $

Choose the correct options:$\dfrac{{10}^2}{{11}^2}$

  1. $\left[\dfrac{{10}}{{11}}\right]^2$

  2. $\left[\dfrac{{100}}{{11}}\right]^2$

  3. $\left[\dfrac{{10}}{{11}}\right]^4$

  4. $\left[\dfrac{{5}}{{11}}\right]^2$


Correct Option: A
Explanation:

$Now\quad \dfrac { { 10 }^{ 2 } }{ 11^{ 2 } } \ =\quad \left( \dfrac { 10 }{ 11 }  \right) ^{ 2 }\left( \because \left( \dfrac { { a }^{ m } }{ { b }^{ m } }  \right) =\left( \dfrac { a }{ b }  \right) ^{ m } \right) $

Choose the correct option:
$\left(\dfrac{5^5\times6^5}{3^5}\right)$

  1. $\left(\dfrac{5\times6}{3}\right)^5$

  2. $\left(\dfrac{5\times6}{3}\right)^6$

  3. $\left(\dfrac{5\times6}{5}\right)^3$

  4. $\left(\dfrac{5\times6}{5}\right)^5$


Correct Option: A
Explanation:

$Now\quad \left( \dfrac { { 5 }^{ 5 }\times { 6 }^{ 5 } }{ { 3 }^{ 5 } }  \right) \quad \ \quad \quad =\quad \left( \dfrac { 5\times 6 }{ 3 }  \right) ^{ 5 }\quad \left( \because \left( \dfrac { { a }^{ m }\times { c }^{ m } }{ { b }^{ m } }  \right) =\left( \dfrac { a\times c }{ b }  \right) ^{ m } \right) $

The value of $(15)^4$ is equal to:
  1. $(15)^4=3^2.5^2$

  2. $(15)^4=3^4.5^4$

  3. $(15)^4=3^3.5^3$

  4. $(15)^4=3^2.5^3$


Correct Option: B
Explanation:
We need to find value of $(15)^4$
It can be written as $(15)^4=(3\times 5)^4$
$=3^4\times 5^4$    ....Using law $(ab)^m=a^m.b^m$
Hence, option B is correct.

Simplify the following using law of exponents.
$\dfrac{9^7}{9^{15}}$

  1. $9^{-8}$

  2. $\dfrac{1}{9^8}$

  3. $9^8$

  4. $9^{1/8}$


Correct Option: A,B
Explanation:

we know,


$\dfrac{a^{m}}{a^{n}}=a^{m-n}$

so,

$\dfrac{9^{7}}{9^{15}}$

$=9^{7-15}$

$=9^{-8}$

$=\dfrac{1}{9^{8}}$

Simplify the following using law of exponents.
$(-6^4)^4$

  1. $(-6)^{16}$

  2. $(-6)^0$

  3. $(-6)^8$

  4. $(-6)^1$


Correct Option: A
Explanation:

we know,


$(a^{m})^{n}=a^{mn}$

so,

$((-6)^{4})^{4}=(-6)^{4*4}$

$=(-6)^{16}$



The value of $\left (\dfrac {a^{-2} \times b^{-3}}{a^{-3}\times b^{-4}}\right )$ is _________.

  1. $a^{-1}\times b$

  2. $a \times b^{-1}$

  3. $(ab)^{-1}$

  4. $ab$


Correct Option: D
Explanation:
We need to find value of $\left (\dfrac {a^{-2} \times b^{-3}}{a^{-3}\times b^{-4}}\right )$
By using $\dfrac {a^m}{a^n}=a^{m-n}$
Then it can be written as,
$a^{-2-(-3)}\times b^{-3-(-4)}$ $=$ $ab$   
Hence, option D is correct.

If $(\sqrt{2})^x + (\sqrt{3})^x = (\sqrt{13})^{\frac{x}{2}}$, then the value of $x$ is ___.

  1. $1$

  2. $2$

  3. $4$

  4. $0$


Correct Option: C
Explanation:

$(\sqrt2)^x+(\sqrt3)^x=(\sqrt{13})^{\frac{x}{2}}$

$\Rightarrow 2^{\frac{x}{2}}+3^{\frac{x}{2}}=13^{\frac{x}{4}}$

$x$ should be the multiple of $4$.
If we put $x=4$
L.H.S$: 2^2+3^2=13$
and R.H.S $: 13^{\frac{4}{4}}=13$
$\therefore x=4$

If $a^2bc^3=5^3$ and $ab^2=5^6$, then $abc$ equals ___.

  1. $5$

  2. $5^2$

  3. $5^3$

  4. $5^{4.5}$


Correct Option: C
Explanation:

$a^2bc^3=5^3$   ......(1)

$ab^2=5^6$      .......(2)
Multiplying equation 1 and 2, we get
$a^3b^3c^3=5^9$
$abc=5^{9/3}=5^3$

The value of $x$, if $5^{x-3}.3^{2x-a} = 225$ is ____.

  1. $3$

  2. $4$

  3. $2$

  4. $5$


Correct Option: D
Explanation:

$225=3^2.5^2=5^{x-3}.3^{2x-a}$

Comparing powers of 5 on both sides 
$x-3=2$
$x=5$

The rationalising factor of $\sqrt[5]{a^2b^3c^4}$ is _____.

  1. $\sqrt[5]{a^3b^2c}$

  2. $\sqrt[5]{a^3bc}$

  3. $\sqrt[5]{a^3b^2c^5}$

  4. $\sqrt[5]{a^3b^6c}$


Correct Option: A
Explanation:

To rationalize $(a^2b^3c^4)^{\frac{1}{5}}$, fifth root must be removed, 

$\therefore$We should multiply it by the factor $(a^3b^2c)^{\frac{1}{5}}$, So thst it will become $abc$.

$\left(\dfrac{5^a}{5^b}\right)^{a+b}.\left(\dfrac{5^b}{5^c}\right)^{b+c}.\left(\dfrac{5^c}{5^a}\right)^{c+a} =$ 

  1. $1$

  2. $4$

  3. $5$

  4. $0$


Correct Option: A
Explanation:

We have, $\Bigr(\dfrac{5^a}{5^b}\Bigl)^{a+b}\cdot\Bigl(\dfrac{5^b}{5^c} \Bigr)^{b+c}\cdot \Bigl(\dfrac{5^c}{5^a} \Bigr)^{c+a}$


$=(5^{a-b})^{a+b}\cdot(5^{b-c})^{b+c}\cdot(5^{c-a})^{c+a}$

$=5^{a^2-b^2}\cdot 5^{b^2-c^2}\cdot 5^{c^2-a^2}\ $

$=\dfrac{5^{a^2}}{5^{b^2}}\cdot \dfrac{5^{b^2}}{5^{c^2}}\cdot \dfrac{5^{c^2}}{5^{a^2}}\\=1$

Comparing the numbers $10^{-49}$ and 2. $10^{-50}$ we may say

  1. the first exceeds the second by 8. $10^{-1}$

  2. the first exceeds the second by 2. $10^{-1}$

  3. the first exceeds the second by 8. $10^{-50}$

  4. the second is five times the first

  5. the first exceeds the second by 5


Correct Option: C
Explanation:

${ 10 }^{ -49 }-2\cdot { 10 }^{ -50 }={ 10 }^{ -50 }(10-2)=8\cdot { 10 }^{ -50 }\ \therefore { 10 }^{ -49 }\hspace{1mm} exceeds\hspace{1mm} 2\cdot { 10 }^{ -50 }\hspace{1mm} by\hspace{1mm} 8\cdot { 10 }^{ -50 }$

If ${2^a} = 3$ and ${9^b} = 4$ then the value of $a.b$ is

  1. $1$

  2. $2$

  3. $3$

  4. $4$


Correct Option: A
Explanation:
 ${ 2 }^{ a }=3$$ a\log _{ 10 }{ 2 } =\log _{ 10 }{ 3 } $$ a= \dfrac { \log _{ 10 }{ 3 }  }{ \log _{ 10 }{ 2 }  }   $  ${ 9 }^{ b }=4$$ b\log _{ 10 }{ 9 } =\log _{ 10 }{ 4 } $$b=\dfrac { \log _{ 10 }{ 4 }  }{ \log _{ 10 }{ 9 }  } $$ b=\dfrac { \log _{ 10 }{ { 2 }^{ 2 } }  }{ \log _{ 10 }{ { 3 }^{ 3 } }  } $$ b=\dfrac { \log _{ 10 }{ { 2 } }  }{ \log _{ 10 }{ { 3 } }  } $

$\therefore a.b= \dfrac { \log _{ 10 }{ 3 }  }{ \log _{ 10 }{ 2 }  }   \times \dfrac { \log _{ 10 }{ { 2 } }  }{ \log _{ 10 }{ { 3 } }  }$


$\therefore a.b=1$

whether the following relation is${{ \frac{1}{{{x^{a - b}}}}} ^{\frac{1}{{a - c}}}}{{ \frac{1}{{{x^{b - c}}}}} ^{\frac{1}{{b - a}}}}{{ \frac{1}{{{x^{c - a}}}}} ^{^{\frac{1}{{c - b}}}}} = 1$

  1. True

  2. False


Correct Option: A

If ${2^{n-m}}=16$ and $3^{n+m}=729$  then $mn=?$

  1. $5$

  2. $4$

  3. $6$

  4. None of the above.


Correct Option: A
Explanation:

$2^{n-m}=16\2^{n-m}=2^4\n-m=4\cdots(1)\3^{n+m}=729\3^{n+m}=3^6\n+m=6\cdots(2)\(1)+(2)\2n=10\\boxed{n=5}\\boxed{m=1}$
$\boxed{nm=5}...Answer$

The sum of roots of the equation $(1.25)^{1-x^2} = (0.4096)^{1+x}$

  1. Infinite

  2. $1$

  3. $2$

  4. $4$


Correct Option: D
Explanation:
$\left ( 1.25 \right )^{1-x^{2}}=\left ( 0.4096 \right )^{1+x}$

$\left ( \dfrac{125}{100} \right )^{1-x^{2}}=\left ( \dfrac{4096}{10000} \right )^{1+x}$

$\left ( \dfrac{5}{4} \right )^{1-x^{2}}=\left ( \left ( \dfrac{8}{10} \right )^{4} \right )^{1+x}$

$\left ( \dfrac{5}{4} \right )^{1-x^{2}}=\left ( \dfrac{4}{5} \right )^{4+4x}$

$\left ( \dfrac{5}{4} \right )^{1-x^{2}}=\left ( \dfrac{5}{4} \right )^{-4-4x}$

$\Rightarrow 1-x^{2}=-4-4x$

$x^{2}-4x-5=0$

$x^{2}-5x+x-5=0$
$x(x-5)+1(x-5)=0$
$(x+1)(x-5)=0$
$x=-1,5$

Therefore, Sum of the roots of equation  is $4$

Find:$\dfrac{\sqrt[3]{108}\times \sqrt[6]{4}}{\sqrt[4]{81}}$

  1. $ 2$

  2. $\frac{\sqrt[6]{4}}{\sqrt[2]{3}}$

  3. $ \sqrt[4]{6}$

  4. $\frac{\sqrt[4]{2}}{\sqrt[2]{3}}$


Correct Option: A
Explanation:

$(\frac{\sqrt[3]{180}\times \sqrt[6]{4}}{\sqrt[4]{81}})\\ ((\frac{27\times4)^{(\frac{1}{4})}\times 2^{(\frac{2}{6})}}{(3^4)^{(\frac{1}{4})}}))\\ =(\frac{3\times 2^{(\frac{2}{3}) }\times 2^{(\frac{1}{3})}}{3})\\= 2^{{(\frac{2}{3})}+{(\frac{1}{3})}}\\=2$

If $(25) _{n}\times (31) _{n}=(1015) _{n}$ then the value of $(13) _{n}\times (25) _{n}$ is $n>0$ :

  1. $(626) _{n}$

  2. $(462) _{n}$

  3. $(716) _{n}$

  4. $(676) _{n}$


Correct Option: A

If $ p= {2} ^{ \tfrac {2} {3}} + {2} ^{ \tfrac {1} {3}} $,then 

  1. ${p}^{3}-6p+6=0 $

  2. ${p}^{3}-3p-6=0 $

  3. ${p}^{3}-6p-6=0 $

  4. ${p}^{3}-3p+6=0 $


Correct Option: C
Explanation:
Given,

$p=2^{\frac{2}{3}}+2^{\frac{1}{3}}$

cubing both sides

$p^3=(2^{\frac{2}{3}}+2^{\frac{1}{3}})^3$

$p^3=\left(2^{\frac{2}{3}}\right)^3+3\left(2^{\frac{2}{3}}\right)^2\cdot \:2^{\frac{1}{3}}+3\cdot \:2^{\frac{2}{3}}\left(2^{\frac{1}{3}}\right)^2+\left(2^{\frac{1}{3}}\right)^3$

$p^3=6+6\cdot \:2^{\frac{2}{3}}+6\cdot \:2^{\frac{1}{3}}\quad $

$p^3=6+6\left ( 2^{\frac{2}{3}}+2^{\frac{1}{3}} \right )$

$p^3=6+6p$

$\therefore p^3-6-6p=0$

$\dfrac{(625)^{6.25} \times (25)^{2.6}}{(625)^{6.75} \times (5)^{1.2}} = ?$

  1. $5$

  2. $10$

  3. $15$

  4. $25$


Correct Option: D
Explanation:
Given,

$\dfrac{625^{6.25}\cdot \:25^{2.6}}{625^{6.75}\cdot \:5^{1.2}}$

$=\dfrac{625^{\tfrac{25}{4}}\cdot \:25^{\tfrac{13}{5}}}{625^{\tfrac{27}{4}}\cdot \:5^{\tfrac{6}{5}}}$

$=\dfrac{(5^4)^{\tfrac{25}{4}}\cdot \:(5^2)^{\tfrac{13}{5}}}{(5^4)^{\tfrac{27}{4}}\cdot \:5^{\tfrac{6}{5}}}$

$=\dfrac{(5^{25})\cdot \:(5)^{\tfrac{26}{5}}}{(5)^{27}\cdot \:5^{\tfrac{6}{5}}}$

$=\dfrac{5^{25+\tfrac{26}{5}}}{5^{27+\tfrac{6}{5}}}$

$=5^{25+\tfrac{26}{5}-27-\tfrac{6}{5}}$

$=5^{-2+\tfrac{20}{5}}$

$=5^{-2+4}$

$=5^2=25$

The value of $\left(\dfrac{1}{64}\right)^{-5/6}$ will be

  1. $8$

  2. $16$

  3. $36$

  4. $32$


Correct Option: D
Explanation:

Given, 

$(\dfrac{1}{64})^{\tfrac{-5}{6}}$

$= {64}^{\tfrac{5}{6}}$


$= ({2^6})^{\frac{5}{6}}$

$= ({2^5})$

$= 32$

Find $x:[3+\left { 2+(1+x^{2}) \right }^{2}]^{2}=144$

  1. $1$

  2. $0$

  3. $5$

  4. $6$


Correct Option: B
Explanation:
Given,

$\left [ 3+\left\{2+\left(1+x^2\right)\right\}^2 \right ]^2=144$

taking square root on both sides, we get,

$\left [ 3+\left\{2+\left(1+x^2\right)\right\}^2 \right ]=12$

$\left\{2+\left(1+x^2\right)\right\}^2=12-3=9$

again taking square root on both sides, we get,

$2+(1+x^2)=3$

$1+x^2=3-2=1$

$x^2=1-1=0$

$\therefore x=0$

THe value of $\dfrac{8^3 + 6^3}{8^2 - 8 \times6 + 6^2}$ is

  1. $10$

  2. $14$

  3. $2$

  4. $15$


Correct Option: B
Explanation:
Given,

$\dfrac{8^3+6^3}{8^2-8 \times 6+6^2}$

$=\dfrac{512+216}{64-48+36}$

$=\dfrac{728}{52}$

$=14$

The product $(32)(32)^{1/6}(32)^{1/36}......$ to $\infty$ is 

  1. $16$

  2. $32$

  3. $64$

  4. $0$


Correct Option: A
Explanation:

$(32)(32)^{1/6}(32)^{1/36}......$ to $\infty = (32)^{1+\dfrac{1}{6}.....\infty}$

sum of infinite GP = a=1  ,  r=$\dfrac{1}{6}$
      $\dfrac{a}{1-r}=\dfrac{1}{1-6}=\dfrac{6}{5}$
$(32)^{\dfrac{6}{5}}=16$

Simplicity
$\left[ \left{ \left( 625 \right) ^{ -\dfrac { 1 }{ 2 } } \right} ^{ -\dfrac { 1 }{ 4 } } \right] $

  1. $\dfrac{1}{\sqrt5}$

  2. $\sqrt5$

  3. 5

  4. None of these


Correct Option: B
Explanation:

$\begin{array}{l}\left[ {{{\left( {{{\left( {625} \right)}^{\frac{{ - 1}}{2}}}} \right)}^{\frac{{ - 1}}{4}}}} \right] = \left[ {{{\left( {{{\left( {{{25}^2}} \right)}^{\frac{{ - 1}}{2}}}} \right)}^{\frac{{ - 1}}{4}}}} \right]\ = \left[ {{{\left( {{{25}^{ - 1}}} \right)}^{\frac{{ - 1}}{4}}}} \right]\ = {25^{\frac{1}{4}}}\ = {5^{2 \times \frac{1}{4}}}\ = {5^{\frac{1}{2}}}\ = \sqrt 5 \end{array}$

If $\displaystyle \log _{16} 8$ = $\displaystyle \frac {3}{m}$, then value of $m$ is equal to 

  1. $1$

  2. $2$

  3. $3$

  4. $4$


Correct Option: D
Explanation:
$\log _{16}8=\dfrac{3}{m}$

$\therefore \dfrac{\log 8}{\log 16}=\dfrac{3}{m}$      ....($\log _ba=\dfrac{\log a}{\log b}$)

$\therefore \dfrac{\log 2^3}{\log 2^4}=\dfrac{3}{m}$   ...($\log a^b=a\log b$)

$\therefore \dfrac{3}{m}=\dfrac{3}{4}$ $ \Rightarrow m = 4$.

Match the numbers in column-I with the rules in column- II

No Column-I No Column-II
1 30 a $n^3+n/2 $
2 63 b $3n^2+3$
3 66 c $n^3+4$
4 110 d $n^2-2n$
5 127 e $n^3-3n$
f $2n^2-1$


Which rule the number 30 follows?

  1. b

  2. c

  3. d

  4. e


Correct Option: A
Explanation:

Substitute the value of $n=3$ in $b$
 $\Rightarrow  3n^2+3=3\times 3^2+3=27+3= 30 $
Hence, option 'A' is correct.

$\displaystyle (64)^{-\tfrac{1}{2}}-(-32)^{-\tfrac{4}{5}}=?$

  1. $\displaystyle \frac{1}{8}$

  2. $\displaystyle \frac{3}{8}$

  3. $\displaystyle \frac{1}{16}$

  4. $\displaystyle \frac{3}{16}$


Correct Option: C
Explanation:

$\displaystyle (64) ^{-\tfrac{1}{2}}-(-32)^{-\tfrac{4}{5}}$
$=\left({2^6}\right)^{\frac{-1}{2}}-\left({(-2)^5}\right)^{\frac{-4}{5}}$
$=(2)^{ -\tfrac { 6 }{ 2 }  }-(-2)^{ -\tfrac { 4\times 5 }{ 5 }  }$
$=(2)^{ -3 }-(-2)^{ -4 }$
$\dfrac { 1 }{ 8 } -\dfrac { 1 }{ 16 } =\dfrac { 1 }{ 16 } $
Answer $C$ option, $ \cfrac { 1 }{ 16 } $

If $a^x=\sqrt{b},b^y = \sqrt [3]{c}$ and $c^z = \sqrt {a}$ then the value of $xyz$

  1. $\displaystyle \frac {1}{2}$

  2. $\displaystyle \frac {1}{3}$

  3. $\displaystyle \frac {1}{6}$

  4. $\displaystyle \frac {1}{12}$


Correct Option: D
Explanation:

$a^x=\sqrt{b}=b^{1/2}$
$a=b^{1/2x}$
$b^y=\sqrt[3]{c}$
$b^y=c^{1/3}$
$b=c^{1/3y}$
$c^z=a^{1/2}$
$c=a^{1/2z}=b^{1/4xz}$
$c^1=c^{1/12xyz}$
$\displaystyle 1= \frac {1}{12xyz}$
$\displaystyle xyz = \frac {1}{12}$

Solve for x ; $\displaystyle \frac{2^{x-3}}{8^{-x}} = \frac{32}{4^{(1/2)x}}$

  1. $2\displaystyle \frac{1}{5}$

  2. $1\displaystyle \frac{1}{5}$

  3. $3\displaystyle \frac{1}{5}$

  4. $1\displaystyle \frac{3}{5}$


Correct Option: D
Explanation:

 $\displaystyle \frac{2^{x-3}}{8^{-x}} = \frac{32}{4^{(1/2)x}}$
$\frac { 2^{ x-3 } }{ 2^{ -3x } } =\frac { { 2 }^{ 5 } }{ 2^{ (2/2)x } } $\ 
${ 2 }^{ x-3+3x }={ 2 }^{ 5-x }$
$4x-3=5-x$
$5x=8$
$x=1\frac { 3 }{ 5 } $
Answer (D)  $1\frac { 3 }{ 5 } $

If $2^a\,>\,4^c\;and\;3^b\,>\,9^a\;and\;a,\,b,\,c$ all positive, then

  1. $c\,<\,a\,<\,b$

  2. $b\,<\,c\,<\,a$

  3. $c\,<\,b\,<\,a$

  4. $a\,<\,b\,<\,c$


Correct Option: A
Explanation:

$2^a\,>\,4^c\;\;\;\;\;\;3^b\,>\,9^a$
$2^a\,>\,2^{2c}\;\;\;\;\;3^b\,>\,3^{2a}$
$a\,>\,2c\;\;\;\;\;\;\;b\,>\,2a$
$\therefore\;a\,>\,c-(i)\;\;\therefore\;b\,>\,a-(ii)$
From (1) & (2), we have
$c\,<\,a\,<\,b$

Find the value of: $[(-2)^{3} \times (-2)^{-4}]^{2}$

  1. $4$

  2. $\dfrac {1}{4}$

  3. $-4$

  4. $-\dfrac {1}{4}$


Correct Option: B
Explanation:

$[(-2)^{3} \times (-2)^{-4}]^{2} = [(-2)^{3-4}]^{2}$

$=[(-2)^{-1}]^{2}$

$=\left (\dfrac {1}{-2}\right )^{2}$$= \dfrac {1}{4}$

So, option $B$ is correct.

Find m so that $\displaystyle \left ( \frac{11^{2}}{13^{2}} \right )^{-6}=\left ( \frac{13}{11} \right )^{m}$

  1. $-12$

  2. $-6$

  3. $6$

  4. $12$


Correct Option: D
Explanation:

$\displaystyle \left ( \frac{11^{2}}{13^{2}} \right )^{-6}=\left ( \frac{11}{13} \right )^{-12}=\left ( \frac{13}{11} \right )^{12}$
Also,$\displaystyle \left ( \frac{13}{11} \right )^{12}=\left ( \frac{13}{11} \right )^{m}$
$\displaystyle \therefore m=12$

Find the value of: $[(-3)^{-4} \div (-3)^{-5}]^{3}$

  1. $-27$

  2. $27$

  3. $\dfrac {1}{27}$

  4. $-\dfrac {1}{27}$


Correct Option: A
Explanation:

$[(-3)^{-4} \div (-3)^{-5}]^{3} = [(-3)^{-4+5}]^{3}$

$=[(-3)^{1}]^{3}$ $= (-3)^{3}$

$= -27$

So, option $A$ is correct.

The value of $(6^{4} \times 7^{2})^{\tfrac {1}{2}}$ is equal to _____

  1. $49$

  2. $42$

  3. $252$

  4. $36$


Correct Option: C
Explanation:

$(6^{4} \times 7^{2})^{\tfrac {1}{2}} = 6^{\tfrac {4}{2}} \times 7^{\tfrac {2}{2}}$
$= 6^{2} \times 7$
$= 36\times 7$
$= 252$

So, option $C$ is correct.

Given $\log _{ 10 }{ x } =a,\log _{ 10 }{ y } =b$

Write down ${ 10 }^{ a-1 }$ in terms of $x$.

  1. $\cfrac{10}{x}$

  2. $10x$

  3. $x$

  4. $\cfrac{x}{10}$


Correct Option: D
Explanation:

$\log _{10} x = a$

$10^a = x$

$\therefore 10^{a – 1} = \dfrac{10^a}{10^ 1} = \dfrac{x}{10}$

Given $\log _{ 10 }{ x } =a,\log _{ 10 }{ y } =b$

Write down ${ 10 }^{ 2b }$

  1. ${y}^{a}$

  2. ${y}$

  3. ${y}^{2}$

  4. ${y}^{b}$


Correct Option: C
Explanation:

$\log _{10} y = b$

$10^b = y$

 $ \therefore 10^{2b} = (10^b)^2 = y^2$

The value of ${({3}^{m})}^{n}$, for every pair of integers $(m,n)$ is 

  1. ${3}^{m+n}$

  2. ${3}^{mn}$

  3. ${3}^{{m}^{n}}$

  4. ${3}^{m}+{3}^{n}$


Correct Option: B
Explanation:

We know that for some positive integers $m$ and $n$, 

$\left( x^{ m } \right) ^{ n }=x^{ m\times n }=x^{mn}$
Therefore, $\left( 3^{ m } \right) ^{ n }=3^{ m\times n }=3^{mn}$
Hence, the value of $\left( 3^{ m } \right) ^{ n }$ is $3^{mn}$.

Simplify the following:
${(-5)}^{4}\times {(-5)}^{-6}$

  1. $\dfrac{1}{25}$

  2. $\dfrac{1}{5}$

  3. $\dfrac{-1}{25}$

  4. None of these


Correct Option: A
Explanation:

we know that,


$\because a^m*a^n=a^{m+n}$

and

$\because \dfrac{1}{a^m}=a^{-m}$
${(-5)}^{4}\times {(-5)}^{-6}$

$=(-5)^{-6+4}$

$=(-5)^{-2}$

$=\dfrac{1}{(-5)^2}$

$=\dfrac1{25}$

$(2^{0} + 4^{-1})\times 2^{2}$ is equal to

  1. $2$

  2. $5$

  3. $4$

  4. $3$


Correct Option: B
Explanation:

As we know that $a^{-b}$ is equal to $1/a^{b}$. Also, $p^{0}=1$ 


So, $(2^{0}+4^{-1})\times 2^{2}=(1+1/4)\times 2^{2}$ 

by using distributive law of multiplication , we get

 $(2^{0}+4^{-1})\times 2^{2}=1\times 2^{2}+1/4\times 2^{2}$ 

$(2^{0}+4^{-1})\times 2^2=4+1/4\times 4$ (because $2^{2}=2\times 2=4$) 

$(2^{0}+4^{-1})\times 2^{2}=4+1=5$

The value of $(4\times 5)^6$ is equal to:

  1. $4^6\times6^5$

  2. $4^6\times5^5$

  3. $4^6\times5^6$

  4. $4^6\times7^6$


Correct Option: C
Explanation:
We need to find value of $(4\times 5)^6$ 

  $=4^6\times 5^6$      .....By using law $(a\times b)^m=a^m\times b^m$

Hence, option C is correct.

The value of $\left(\dfrac{x^q}{x^r}\right)^{\dfrac{1}{qr}} \times \left(\dfrac{x^r}{x^p}\right)^{\dfrac{1}{rp}}\times \left(\dfrac{x^p}{x^q}\right)^{\dfrac{1}{pq}}$ is equal to ___.

  1. $x^{\frac{1}{p}+\frac{1}{q}+\frac{1}{2}}$

  2. $0$

  3. $x^{pq+qr+rp}$

  4. $1$


Correct Option: D
Explanation:

$(x^{q-r})^{\cfrac{1}{qr}}\times (x^{r-p})^{\cfrac{1}{rp}}\times (x^{p-q})^{\cfrac{1}{pq}} $


$=x^{\cfrac{q-r}{qr}}\times x^{\cfrac{r-p}{rp}}\times x^{\cfrac{p-q}{pq}}$
On adding all the powers of $x$, we get
$\Rightarrow x^{\bigl(\cfrac{q-r}{qr}+\cfrac{r-p}{rp}+\cfrac{p-q}{pq}\bigr)}$

$=x^{\cfrac{p(q-r)+q(r-p)+r(p-q)}{pqr}}$

$=x^{\cfrac{0}{pqr}}=1$

$\left(\dfrac{1}{x^{a-b}}\right)^{\tfrac{1}{(a-c)}}. \left(\dfrac{1}{x^{b-c}}\right)^{\tfrac{1}{(b-a)}}. \left(\dfrac{1}{x^{c-a}}\right)^{\tfrac{1}{(c-b)}}=$

  1. $0$

  2. $1$

  3. $a+b+c$

  4. $(a-b+c)^2$


Correct Option: B
Explanation:

We can write the given equation as, 

$(x^{b-a})^{\frac{1}{a-c}}\cdot (x^{c-b})^{\frac{1}{b-a}}\cdot (x^{a-c})^{\frac{1}{c-b}}$

$=x^{\cfrac{b-a}{a-c}}\cdot x^{\cfrac{c-b}{b-a}}\cdot x^{\cfrac{a-c}{c-b}}$
On adding all the powers of $x$, We get
$x^{\Bigl(\cfrac{(b-a)^2(c-b)+(c-b)^2(a-c)+(a-c)^2(b-a)}{(a-c)(b-c)(c-b)}\Bigr)}\ =x^0=1$

The $100^{th}$ root of $10^{(10^{10})}$ is ___.

  1. $10^{8^{10}}$

  2. $10^{10^{8}}$

  3. $(\sqrt{10})^{(\sqrt{10})^{10}}$

  4. $10(\sqrt{(10)})^{\sqrt{10}}$


Correct Option: B
Explanation:

$100th $ root of $10^{(10^{10})}=(10^{(10^{10})})^{\frac{1}{100}}$


$\Rightarrow 10^{(\frac{10^{10}}{100})}=10^{(10^8)}$

Consider the following statements.
Assertion $(A): a^0 = 1, a\neq 0$
Reason $(R): a^m\div a^n = a^{m-n}$, where $m,n$ being integers.
Which of the following options hold?

  1. Both $A$ and $R$ are true and $R$ is the correct explanation of $A$.

  2. Both $A$ and $R$ are true and $R$ is not the correct explanation of $A$.

  3. $A$ is true and $R$ is false.

  4. $A$ is false but $R$ is true.


Correct Option: B
Explanation:

$a^0=1\,\,(\text{Where} \,a\ne 0)$  

$\therefore $   Assertion is true
And $\dfrac{a^m}{a^n}=a^{m-n}$
2nd statement is also true, but not the correct explanation of first statement.

The value of $\cfrac { { 2 }^{ 2n-2 } }{ { 2 }^{ n(n-1) } }-\cfrac { { 8 }^{ n-1 } }{ { 2 }^{ (n-1)(n+1) } } $ will be

  1. $2$

  2. $0$

  3. $\dfrac {1}{2}$

  4. $\dfrac {1}{4}$


Correct Option: B
Explanation:
Given,

$\dfrac{2^{2n-2}}{2^{n(n-1)}} - \dfrac{8^{n-1}}{2^{(n-1)(n+1)}}$

$=\dfrac{2^{2(n-1)}}{2^n \times 2^{(n-1)}} - \dfrac{2^{3(n-1)}}{2^{(n-1)(n+1)}}$

$=\dfrac{2^2\times 2^{(n-1)}}{2^n \times 2^{(n-1)}} - \dfrac{2^3\times 2^{(n-1)}}{2^{(n-1)(n+1)}}$

$=\dfrac{2^2\times 2^{(n-1)}}{2^n \times 2^{(n-1)}} - \dfrac{2^3\times 2^{(n-1)}}{2^{(n-1)}2^{(n+1)}}$

$=\dfrac{2^2}{2^n}-\dfrac{2^3}{2^{n+1}}$

$=\dfrac{2^2}{2^n}-\dfrac{2^3}{2^n \times 2^1}$

$=\dfrac{2^2}{2^n}-\dfrac{2^2}{2^n}$

$=0$

Find the sum of all values of $x$, so that $16^{\left(x^{2}+3x-1\right)}=8^{\left(x^{2}+3x+2\right)}$.

  1. $0$

  2. $3$

  3. $-3$

  4. $-5$


Correct Option: C
Explanation:

Given, $16^{(x^2 + 3x -1)} = 8^{(x^2 + 3x + 2)}$


As, 16 = $2^4 and \ \ \ 8 = 2^3$


$2^{4(x^2 + 3x -1)} = 2^{3(x^2 + 3x + 2)}$

So, we can write 

${4(x^2 + 3x -1)} = {3(x^2 + 3x + 2)}$

${4x^2 + 12x - 4} = {3x^2 + 9x + 6}$

${4x^2 + 12x - 4} - {(3x^2 + 9x + 6)} = 0$
$4x^2 + 12x - 4 - 3x^2 - 9x - 6 = 0$

$x^2 + 3x - 10  = 0$

$x^2 + 5x - 2x - 10  = 0$

$x(x + 5) - 2(x + 5)  = 0$

$(x - 2)(x + 5)  = 0$

So, $x = 2, - 5$

Sum of values of $x = 2 + (-5) = -3$

If  $n$  is a natural number, then  $4 ^ { n } - 3 ^ {  n }$  ends with a digit  $x.$  The number of possible values of  $x$  is

  1. $3$

  2. $8$

  3. $5$

  4. $6$


Correct Option: A
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