Question

若有理数x,y满足x的绝对值=7,y的绝对值=4,且x+y的绝对值=x+y,则ɧ

Answer 1

若有理数x,y满足x的绝对值=7,y的绝对值=4,且x+y的绝对值=x+y,

x=-7或7,y=4或-4

x+y>0

所以

x=7,y=4

x-y=3

x=7,y=-4

x-y=11