xy-xz+y-z 急>
问题描述：
xy-xz+y-z 急>
答
xy-xz+y-z
=x(y-z)+(y-z)
=(x+1)(y-z)
xy-xz+y-z 急>
xy-xz+y-z
=x(y-z)+(y-z)
=(x+1)(y-z)