Determine if a Polynomial 9-12n^2+4n^3-7n

A polynomial is a combination of terms separated using ${\displaystyle +}$ or ${\displaystyle -}$ signs. Polynomials cannot contain any of the following:

1. Variables raised to a negative or fractional exponent. (${\displaystyle 2x^{-2}}$,${\displaystyle x^{\frac{1}{2}}}$,${\displaystyle \dots }$).

2. Variables in the denominator. (${\displaystyle \frac{1}{x}}$,${\displaystyle \frac{1}{x^2}}$,${\displaystyle \dots }$).

3. Variables under a radical. (${\displaystyle \sqrt{x}}$,${\displaystyle \sqrt[3]{x}}$,${\displaystyle \dots }$).

4. Special features. (trig functions, absolute values, logarithms, ${\displaystyle \dots }$).

Determine if the expression breaks any of the rules.

Does not break any of the rules