Упрастите выражения 6a(a-1)-2a^2(3-a)
6а^2-6а-6а^2+2а^2=-6а+2а^2=2а(а-3)
6а^2-6а-6а^2+2а^3=2а^3
6а^2-6а-6а^2+2а^3=2а^3-6а=2а(а^2-3)