Question

This is about exponents

Answer 1

B

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