## Precalculus: Concepts Through Functions, A Unit Circle Approach to Trigonometry (3rd Edition)

Monomials have the form: $$ax^k$$ where $a$ is a constant, $x$ is a variable, and $k$ is a non-negative integer (the degree). Monomials in two variables have the form: $$ax^ny^m$$ where $x$ and $y$ are both considered the "variables" with the degree being the sum $n+m$. The expression $\frac{-2x^2}{y^3}=-2x^2y^{-3}$ is not a monomial because it does not match either form above (the degree on $y$ is negative).