-(x-y+1)乘以(x-y-1)怎么去括号
问题描述：
-(x-y+1)乘以(x-y-1)怎么去括号
答
这是个平方差
-(x-y+1)(x-y-1)
=-[x^2-(y-1)^2]
=(y-1)^2-x^2
=y^2-2y+1-x^2如何去掉负号 这是因式分解得来的噢
乘进去就行了
-(x-y+1)(x-y-1)
=(x-y+1)(-x+y+1)