[tex]\bf ~\hspace{7em}\textit{negative exponents}
\\\\
a^{-n} \implies \cfrac{1}{a^n}
~\hspace{4.5em}
a^n\implies \cfrac{1}{a^{-n}}
~\hspace{4.5em}
\cfrac{a^n}{a^m}\implies a^na^{-m}\implies a^{n-m}
\\\\[-0.35em]
\rule{34em}{0.25pt}\\\\
\cfrac{y^3z^5}{y^4z}\implies \cfrac{y^3z^5}{y^4z^1}\implies \cfrac{z^5\cdot z^{-1}}{y^{-3}y^4}\implies \cfrac{z^{5-1}}{y^{-3+4}}\implies \cfrac{z^4}{y}[/tex]
