Question

若x.y是有理数,且x的绝对值-x=0,y的绝对值+y=0,y的绝对值＞x的绝对值.化简x的绝对值-y的绝对值-x+y

Answer 1

|x|-x=0 |x| =x →x=0或 1

|y|+y=0 |y|=-y → y=0或-1

因为 |y| ＞|x| 所以x=0 y=-1

|x|- |y|-x+y

=0-1-0+(-1)

=-2