(x-y)的平方-(x+y)的平方怎么计算? - 知识问答

(x-y)的平方-(x+y)的平方怎么计算?

5个回答

(x-y)²-(x+y)²
=【(x-y)+(x+y)】【(x-y)-(x+y)】
=(x-y+x+y)(x-y-x-y)
=2x * (-2y)
=-4xy

相关问题