若-(a-5)是负数,则a-5()0 若-[-(x+y)]是负数,则x+y () 0

问题描述:

若-(a-5)是负数,则a-5()0 若-[-(x+y)]是负数,则x+y () 0

止住的回想,
若-(a-5)是负数,则a-5>0
若-[-(x+y)]是负数,则X+Y<0