Question

解方程 解方程组1/(x+y)-1/(x-y)=3/20 2/(x+y)+3/(x+y)=19/20 要过程

Answer 1

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.