1/(x+y)-1/(x-y)=3/20 (1)
2/(x-y)+3/(x+y)=19/20 (2)
(2)+(1)*2得
5/(x+y)=25/20
x+y=4 (3)
(2)- (1)*3得
5/(x-y)=10/20
x-y=10 (4)
(3),(4)联立解得x=7,y=-3
题目的第二个我擅自把2/(x+y)改为了2/(x-y),
如果不是原题,我重做.