Algebra: A Combined Approach (4th Edition)

Base: $x$ Exponent: 2
We know that an exponential expression is in the form $a^{n}$ (where $a$ is the base and $n$ is the exponent). Therefore, the expression $5x^{2}$ has a base of x and an exponent of 2. Since the 5 is not in parentheses with the $x$, we know that the exponent is only applied to the $x$.