Формулы сокращённого умножения
((a³-2a²)/(3a+3))÷((a²-3a+2)/(a+1))=((a³-2a²)*(a+1)/(3*(a+1)*(a²-2a-a+2))= =a²*(a-2)/(3*(a*(a-2)-(a-2))=a²*(a-2)/(3*(a-2)*(a-1))=a²/(3a-3).