[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{5y^3}{(5y)^{-2}}\implies 5y^3(5y)^2\implies 5y^3(5^2y^2)\implies 5\cdot 5^2\cdot y^3\cdot y^2
\\\\\\
5^{1+2}y^{3+2}\implies 5^3y^5\implies 125y^5[/tex]