(aa-bb)(aa-bb)/(a-b)(a-b)

问题描述:

(aa-bb)(aa-bb)/(a-b)(a-b)

(aa-bb)(aa-bb)/(a-b)(a-b)
=(a²-b²)²/(a-b)²
=[(a-b)(a+b)]²/(a-b)²
=(a+b)²