Question

wht is the answer pls tell fast
chapter name : exponents
class 8th cbse​

Answer 1

Answer:

option no. b)........

Answer 2

Answer:

$\dfrac{81}{169}$

Step-by-step explanation:

$\Bigg [ \Bigg ( \dfrac{1}{2} \Bigg )^{-1} +\Bigg ( \dfrac{2}{3} \Bigg )^2 - \Bigg ( \dfrac{3}{4} \Bigg )^0 \Bigg ]^{-2}$

$\mathbb{LAWS \ OF \ EXPONENTS}$

$\rm\dashrightarrow x^0=1$

$\rm\dashrightarrow \Bigg ( \dfrac{x}{m} \Bigg )^n = \dfrac{x^n}{m^n}$

$\rm\dashrightarrow x^{-m} =\dfrac{1}{x^m}$

Therefore,

$\dashrightarrow\Bigg [ \Bigg ( \dfrac{2}{1} \Bigg )^{1} +\dfrac{2^2}{3^2} - 1 \Bigg ]^{-2}$

$\dashrightarrow\Bigg [ 2 +\dfrac{4}{9} - 1 \Bigg ]^{-2}$

$\dashrightarrow\Bigg [ 1+\dfrac{4}{9} \Bigg ]^{-2}$

$\dashrightarrow\Bigg [ \dfrac{9}{9}+\dfrac{4}{9} \Bigg ]^{-2}$

$\dashrightarrow\Bigg [ \dfrac{13}{9} \Bigg ]^{-2}$

$\dashrightarrow\Bigg [ \dfrac{9}{13} \Bigg ]^{2}$

$\dashrightarrow\dfrac{9^2}{13^2}$

$\bf\dashrightarrow\dfrac{81}{169}$

Hence, option b is correct!