[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}}}}\\\\
-------------------------------\\\\[/tex]
[tex]\bf y=a^x\quad
\begin{cases}
x=-3\\
y=1
\end{cases}\quad 1=a^{-3}\implies 1=\cfrac{1}{a^3}\implies a^3=\cfrac{1}{1}
\\\\\\
a=\sqrt[3]{\cfrac{1}{1}}\implies a=1\qquad thus\qquad \boxed{y=(1)^x}[/tex]