a(a+b)(a-b)-a(a-b)^2,提公因式

问题描述:

a(a+b)(a-b)-a(a-b)^2,提公因式

a(a+b)(a-b)-a(a-b)^2
=a(a+b)(a-b)-a(a-b)(a-b)
=a(a-b)[(a+b)-(a-b)]
=a(a-b)(a+b-a+b)
=ab^2(a-b)