Please help. I need it by tonight
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[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] ~\dotfill\\\\ x^{-3}\cdot x^3\cdot y^{-4}\implies \cfrac{1}{\begin{matrix} x^3 \\[-0.7em]\cline{1-1}\\[-5pt]\end{matrix} }\cdot ~~\begin{matrix} x^3 \\[-0.7em]\cline{1-1}\\[-5pt]\end{matrix}~~ \cdot \cfrac{1}{y^4}\implies \cfrac{1}{y^4}[/tex]