Chapter 5 - Exponents and Polynomials - 5.2 - Multiplying Monomials - Problem Set 5.2 - Page 201: 72

$-32x^{8}$

Using the laws of exponents, the given expression, $ (-2x)^3(4x^5) ,$ simplifies to \begin{array}{l}\require{cancel} \left((-2)^{1(3)}x^{1(3)}\right)(4x^5) \\\\= \left((-2)^{3}x^{3}\right)(4x^5) \\\\= \left(-8x^{3}\right)(4x^5) \\\\= (-8)(4)x^{3+5} \\\\= -32x^{8} .\end{array}