## College Algebra (10th Edition)

RECALL: (1) A monomial is a product of a constant and some variable/s whose exponents are nonnegative integers. (2) The degree of a monomial is the sum of the exponents of its variables. Using the rule $\dfrac{1}{a^m} = a^{-m}$, the given expression is equivalent to: $=-2x^2 \cdot \frac{1}{y^3} \\=-2x^2 \cdot y^{-3} \\=-2x^2y^{-3}$ The exponent of $y$ is $-3$, which is not a nonnegative integer. Thus, the given expression is NOT a monomial.