Chapter 5 - Section 5.3 - Special Products - Exercise Set - Page 367: 13

$7-32x-15x^2$

Using $(a+b)(c+d)=ab+ad+bc+bd$ or the FOIL Method, the product of the given expression, $ (7+3x)(1-5x) ,$ is \begin{array}{l}\require{cancel} 7(1)+7(-5x)+3x(1)+3x(-5x) \\\\= 7-35x+3x-15x^2 \\\\= 7-32x-15x^2 .\end{array}