Chapter 5 - Section 5.4 - Polynomials in Several Variables - Exercise Set - Page 375: 38

$-a^3b+ab^{2}-b^{4}$

Using the Distributive Property, the product of the given expression, $ -b(a^3-ab+b^3) ,$ is \begin{array}{l}\require{cancel} -b(a^3)-b(-ab)-b(b^3) \\\\= -a^3b+ab^{1+1}-b^{1+3} \\\\= -a^3b+ab^{2}-b^{4} .\end{array}