Question

What is the value of xx) = 9^x when x= -2?A. 1/81B. 81C. 1/81D. 18​

Answer 1

Answer:

C. $9^{-2} = \frac{1}{81}$

Step-by-step explanation:

Given

$9^{x}$

Required

Find the expression where x - 2

$9^{x}$

Substitute 2 for x

$9^{-2}$

From law of indices which states

$a^{-b} = \frac{1}{a^b}$

So, the expression becomes

$9^{-2} = \frac{1}{9^2}$

Expand the denominator

$9^{-2} = \frac{1}{9 * 9}$

$9^{-2} = \frac{1}{81}$

Hence, $9^{x}$ is $\frac{1}{81}$ when x = 2