【因式分解(x2-y2)-(x-y)2快】
因式分解(x2-y2)-(x-y)2
快
解
(x²-y²)-(x-y)²
=(x-y)(x+y)-(x-y)²
=(x-y)[(x+y)-(x-y)]
=(x-y)×2y
=2y(x-y)