求一道初二方程,急
问题描述:
求一道初二方程,急
如图
x-y/2+x+y/1=1/4和x+y/1-x-y/1=1,是方程组
答
2/(x-y)+1/(x+y)=1/4 (1)
1/(x+y)-1/(x-y)=1 (2)
(1)-(2)得
3/(x-y)=-3/4
x-y=-4 (3)
(1)+(2)*2得
3/(x+y)=9/4
x+y=4/3 (4)
(3)+(4) 得
x=-4/3,y=8/3