Chapter 1 - Introduction to Algebraic Expressions - 1.8 Exponential Notation and Order of Operations - 1.8 Exercise Set - Page 67: 86

$34x^2+11x$

Using $a(b+c)=ab+ac$ or the Distributive Property and then combining like terms, the given expression, $ 6x^2-x+4(7x^2+3x) $, simplifies to \begin{array}{l}\require{cancel} 6x^2-x+4(7x^2)+4(3x) \\\\= 6x^2-x+28x^2+12x \\\\= (6x^2+28x^2)+(-x+12x) \\\\= 34x^2+11x .\end{array}