Answer
$24r^2-15r$
Work Step by Step
We start with the given expression: $3(2r+4r^2-7r+4r^2)$
We apply the distributive property by multiplying $3$ by each of the terms inside the parentheses, and adding these products: $$3(2r)+3(4r^2)+3(-7r)+3(4r^2)=6r+12r^2-21r+12r^2$$
We combine like terms (terms with the same exponent) by adding them: $24r^2-15r$
