Chapter 5 - Exponents and Polynomials - 5.2 - Multiplying Monomials - Problem Set 5.2 - Page 201: 66

$4x^3-11x^2+x$

Using $a(b+c)=ab+ac$, or the Distributive Property, and then combining like terms, the given expression, $ 3x(2x^2-x+5)-2x(x^2+4x+7) ,$ simplifies to \begin{array}{l}\require{cancel} 6x^3-3x^2+15x-2x^3-8x^2-14x \\\\= (6x^3-2x^3)+(-3x^2-8x^2)+(15x-14x) \\\\= 4x^3-11x^2+x .\end{array}