[tex]\bf \left.\qquad \qquad \right.\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}}}}\\\\
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f(x)=2^x\qquad x=-2\implies f(x)=2^{-2}\implies f(x)=\cfrac{1}{2^2}
\\\\\\
f(x)=\cfrac{1}{4}\implies f(x)=0.\underline{250}\impliedby \textit{3 decimals, thousandths}[/tex]