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

$\dfrac{8}{a^{15}}$
Using the laws of exponents, the given expression, $(2a^{-5})^{3}$, is equivalent to \begin{array}{l} 2^{3}a^{-5(3)} \\\\= 8a^{-15} \\\\= \dfrac{8}{a^{15}} .\end{array}