[tex]\bf ~~~~~~~~~~~~\textit{negative exponents}
\\\\
a^{-n} \implies \cfrac{1}{a^n}
\qquad \qquad
\cfrac{1}{a^n}\implies a^{-n}
\qquad \qquad
a^n\implies \cfrac{1}{a^{-n}}
\\\\
-------------------------------\\\\
-\cfrac{5p^5q^4}{8p^2q^2}\implies -\cfrac{5}{8}\cdot \cfrac{p^5q^4}{p^2q^2}\implies -\cfrac{5}{8}\cdot p^5p^{-2}q^4q^{-2}
\\\\\\
-\cfrac{5}{8}\cdot p^{5-2}q^{4-2}\implies -\cfrac{5\stackrel{\downarrow }{p^3}q^2}{8}[/tex]