remember the exponential rules and treat them regularly
[tex]x^{-m}=\frac{1}{x^m}[/tex]
and
[tex](x^m)(x^n)=x^{m+n}[/tex]
and
[tex]\frac{x^m}{x^n}=x^{m-n}[/tex]
that's baseically all you need to know, as long as you understand the rules
here are some examples
[tex]x^{-3}=\frac{1}{x^3}[/tex]
[tex](x^{-4})(x^2)=x^{-4+2}=x^{-2}=\frac{1}{x^2}[/tex]
[tex]\frac{x^{-2}}{x^3}=x^{-2-3}=x^{-5}=\frac{1}{x^5}[/tex]
