## Elementary and Intermediate Algebra: Concepts & Applications (6th Edition)

$\color{red}{\text{This expression is NOT a polynomial}}$.
Remember that a term is considered as a monomial ONLY IF it is a PRODUCT of constants and/or variables. In this item, the terms are $\dfrac{3}{x^4}$, $-\dfrac{1}{x}$, and $13$; however, the first two terms present are QUOTIENTS of constants and/or variables. Therefore, $\color{red}{\text{this expression is NOT a polynomial}}$.