Question

This is about exponents

Answer 1

Answer:

B

Step-by-step explanation:

Using the rules of exponents

$a^{m}$ × $a^{n}$ ⇔ $a^{(m+n)}$ and

$a^{0}$ = 1, then

$9^{x}$ × $9^{-x}$

= $9^{(x-x)}$

= $9^{0}$ = 1 → B