|x|=7,|y|=12,且|x+y|=—(x+y),求x+y的值

问题描述:

|x|=7,|y|=12,且|x+y|=—(x+y),求x+y的值

|x|=7,|y|=12,且|x+y|=—(x+y)≥0

x+y≤0

所以

  1. x=7,y=-12

    x+y=7-12=-5

  2. x=-7,y=-12

    x+y=-7-12=-19