[tex]~\hspace{7em}\textit{negative exponents} \\\\ a^{-n} \implies \cfrac{1}{a^n} ~\hspace{4.5em} a^n\implies \cfrac{1}{a^{-n}} \\\\[-0.35em] \rule{34em}{0.25pt}\\\\ x^6~~ = ~~9^{-3}\implies x^6~~ = ~~(3^2)^{-3}\implies x^6~~ = ~~3^{-6} \\\\\\ x^6~~ = ~~(3^{-1})^6\implies x=3^{-1}\implies x=\cfrac{1}{3^1}\implies x=\cfrac{1}{3}[/tex]