# Is y = 3^x an exponential function?

Yes - it is in the form $y = {a}^{x}$ with $a > 1$ so it is an exponentially growing function.
The term "the exponential function" is used of ${e}^{x}$, but any function $f \left(x\right) = {a}^{x}$ with $a > 0$ and $a \ne 1$ is an exponential function.
If $k = {\log}_{e} \left(a\right)$ then ${a}^{x} = {e}^{k x}$