Answer:
By solving the exponent as if it were positive, then taking the inverse of the number.
For Example:
[tex]3^{-2} = 9^{-1} = 1/9\\\\2^{-3} = 8^{-1} = 1/8[/tex]
[tex]x^{-4} = \frac{1}{x^{4}}[/tex]