Chapter 5 - Exponents and Polynomials - 5.2 - Multiplying Monomials - Problem Set 5.2 - Page 200: 58

$15x^4y+35x^3y-45x^2y$

Using $a(b+c)=ab+ac$ (or the Distributive Property), the given expression, $ 5x^2y(3x^2+7x-9) ,$ is equivalent to \begin{array}{l}\require{cancel} 5x^2y(3x^2)+5x^2y(7x)+5x^2y(-9) \\\\= 15x^4y+35x^3y-45x^2y .\end{array}