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

$5x^3$ and $(5x)^3$ are not equivalent expressions because $(5x)^3=125x^3$.
RECALL: $(ab)^m=a^mb^m$ Thus, $(5x)^3=5^3x^3=125x^3$ Therefore, $5x^3$ and $(5x)^3$ are not equivalent expressions.