化简后再求值(a+1)(aa-2a-3)+(a-1)(aa-2)-(2aa-1)(a+1)其中a=-1
问题描述:
化简后再求值(a+1)(aa-2a-3)+(a-1)(aa-2)-(2aa-1)(a+1)其中a=-1
答
原式=(a³-a²-5a-3)+(a³-a²-2a+2)-(2a³+2a²-a-1)
=a³-a²-5a-3+a³-a²-2a+2-2a³-2a²+a+1
=-4a²-6a
=-4+6
=2