#### Answer

The given function is a rational function.
The function is not a polynomial function because there is a variable in the denominator.

#### Work Step by Step

RECALL:
(1) A function $f(x)$ is a polynomial function if $f(x) = a_nx^n+a_{n-1}x^{n-1}+a_{n-2}x^{n-2}+...+a_1x+a_0$, where $a_n\ne0$.
(2) A function $f(x)$ is a rational function if $f(x) = \dfrac{p(x)}{q(x)}$ where $p(x)$ and $q(x)$ are polynomial functions and $q(x) \ne 0$.
Note that the given function is in the same form as the one in (2) above.
Thus, the given function is a rational function.
The function is not a polynomial function because it has a variable in the denominator.