Question

What are the values of f(x) = 9^x when x= -2?

a) 1/81
b) 81
c) 1/18
d) 18

Answer 1

A. 1/81

Explanation:

1. f(x)=9^x (Original problem)
2. x= -2 . ( Exponent (x) equals to -2)
3. 9^-2 (Plug -2 into x)

Since the exponent is negative, the final answer is a reciprocal and the exponent becomes positive.

4. 1/(9^2) ( Reciprocal of 9^-2)

= 1/81 ( Simplify 1/9^2 = 1/9^2)

Answer 2

(a)

Explanation:

using the rule of exponents

•
`a^(-m)` ⇔
`(1)/(a^(m) )`, hence

`9^(-2)` =
`(1)/(9^(2) )` =
`(1)/(81)` → (a)