(3a-a^2)^2-a^2(a-2)(a+2)+2a(7+3a^2)

●9а^2-6а^3+а^4-а^4+4а^2+14а+6а^3=0 ●9а^2+4а^2+14а=0 ●13а^2+14а=0 ●а (13а+14)=0 ●а1=0 ●а2=-14/13