Simplify $4(3r^3+5r-6)-6(2r^3-r^2+4r)$, and express your answer in the form $Ar^2 + Br + C$, where $A$, $B$, and $C$ are integers.
To simplify this expression, I need to apply the distributive property and combine like terms. First, I distribute the 4 and the -6 to the terms inside the parentheses: $4(3r^3+5r-6)-6(2r^3-r^2+4r) = 12r^3+20r-24-12r^3+6r^2-24r$. Next, I look for the terms that have the same degree of r and add or subtract them: $12r^3+20r-24-12r^3+6r^2-24r = 6r^2-4r-24$. This is already in the form $Ar^2 + Br + C$, where $A=6$, $B=-4$, and $C=-24$. 