如果x-y=2,那么4-x+y=
问题描述:
如果x-y=2,那么4-x+y=
答
4-x+y
=4-(x-y)
=4-2
=2
如果x-y=2,那么4-x+y=
4-x+y
=4-(x-y)
=4-2
=2