(m+n)(x-y)+(m-n)(y-x)
问题描述:
(m+n)(x-y)+(m-n)(y-x)
答
解
(m+n)(x-y)+(m-n)(y-x)
=(m+n)(x-y)-(m-n)(x-y)
=(x-y)(m+n-m+n)
=2n(x-y)