Answer
$y(x)=(\frac{1}{e})^x$
Work Step by Step
Observe that the graph is of the form $y=b^x$. To find the equation of the graph, we need to find the value of $b$. To find this value, we substitute values from the point $(-1,e)$. We get $b=\frac{1}{e}$. Thus the equation is $y(x)=(\frac{1}{e})^x$.
$y=b^x\rightarrow{e}=b^{-1}\rightarrow{e}=\frac{1}{b}\rightarrow{b}=\frac{1}{e}$
$y(x)=(\frac{1}{e})^x$
