Distribute sum groups
5r(r^2 - 6r + 4) -4(r^2 - 6r + 4)
Distribute
5r^3 - 30r^2 + 20r - 4(r^2 - 6r + 4)
Distribute
5r^3 - 30r^2 + 20r - (4r^2 - 24r + 16)
Simplify brackets
5r^3 - 30r^2 + 20r - 4r^2 + 24r - 16
Collect like terms
5r^3 (-30r^2 - 4r^2) + (20 + 24r) - 16
Simplify
5r^3 - 34r^2 + 44r - 16
