[tex]\bf \cfrac{1}{-5z^{-5}}\\\\
-------------------------\\\\
a^{-{ n}} \implies \cfrac{1}{a^{ n}}\qquad \qquad
\cfrac{1}{a^{ n}}\implies a^{-{ n}}
\\ \quad \\
% negative exponential denominator
a^{{ n}} \implies \cfrac{1}{a^{- n}}
\qquad \qquad
\cfrac{1}{a^{- n}}\implies \cfrac{1}{\frac{1}{a^{ n}}}\implies a^{{ n}} \\\\
-------------------------\\\\
thus
[/tex]
[tex]\bf -\cfrac{1}{5}\cdot \cfrac{1}{z^{-5}}\implies -\cfrac{1}{5}\cdot \cfrac{1}{\frac{1}{z^5}}\implies -\cfrac{1}{5}\cdot \cfrac{\frac{1}{1}}{\frac{1}{z^5}}\implies -
\cfrac{1}{5}\cdot \cfrac{1}{1}\cdot \cfrac{z^5}{1}
\\\\\\
-\cfrac{z^5}{5}[/tex]
