if you meant simplification,
[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}}\\\\[-0.35em]
\rule{31em}{0.25pt}\\\\
2^{y+1}\div 2^y\implies \cfrac{2^{y+1}}{2^y}\implies 2^{y+1}\cdot 2^{-y}\implies 2^{(y+1)-y}\implies 2^1\implies 2 [/tex]
