Question

How do you solve for x in `9^x=1/81`?

Answer 1

`x=-2`

Explanation:

First of all, observe that `9^2=81`. Then, remember how negative powers work:

`a^{-b} = 1/a^{b}`.

So, we have that `1/81 = 1/9^2 = 9^{-2}`.

Now, we know that `9^x=9^(-2)`.

And so `x=-2`.