Answer
$f(x)=3^x$
Work Step by Step
Substituting $x=
2
$ and $f(x)=
9
$ in the given function, $f(x)=a^x$, then the value of $a$ is
\begin{array}{l}\require{cancel}
9=a^2
\\\\
a=\pm\sqrt{9}
\\\\
a=\pm3
.\end{array}
Since the base of an exponential function cannot be negative, then $a=3$. Hence, the equation of the given graph is $
f(x)=3^x
.$
