Question

Is $x^3-\frac{1}{x{a}^3}$ a polynomial or not?

Answer 1

Given expression $x^3-\frac{1}{x{a}^3}$.

It is not a polynomial as one of the terms has negative power as an exponent, $\frac{1}{x{a}^3}=\frac{x^{-1}}{a^3}$.

Hence, it is not a polynomial.