先化简再求值（a+1)²-(a+1)(a+3),其中a=-2

先化简再求值（a+1)²-(a+1)(a+3),其中a=-2
先化简再求值（a+1)²-(a+1)(a+3),其中a=-2

先化简再求值（a+1)²-(a+1)(a+3),其中a=-2
（a+1)²-(a+1)(a+3)
=a²+2a+1-a²-4a-3
=-2a-2
=-2x(-2)-2
=4-2
=2

（a+1)²-(a+1)(a+3),
=a²+2a+1-(a²+a+3a+3)
=a²+2a+1-a²-4a-3
=-2a-2
原式==-2x(-2)-2=2