绝对值肯定≥0,正数的相反数是负数,负数的相反数是正数,只有0的相反数为本身,所以有
|2x-3|=0
|y+3|=0
解得:x=3/2,y=-3
x+y=-3/2
x+y的相反数即-(x+y)=3/2