When you have a negative exponent, you move the base with the negative exponent to the other side of the fraction to make the exponent positive.
For example:
[tex]5^{-2}[/tex] or [tex]\frac{5^{-2}}{1}=\frac{1}{5^2} =\frac{1}{25}[/tex]
[tex]\frac{1}{x^{-4}}=\frac{x^4}{1}[/tex] or [tex]x^4[/tex]
[tex]3x^{-5}[/tex] or [tex]3^1x^{-5}=\frac{3}{x^5}[/tex]
[tex]9a^{-1}[/tex] Make the exponent positive
[tex]\frac{9}{a}[/tex] (this is as far as you can simplify)
