5x-1/3y=2 ,5x+2/3y=1
问题描述：
5x-1/3y=2 ,5x+2/3y=1
答
5x-1/3y=2 ,(1)
5x+2/3y=1 (2)
(2)-(1)
y=-1
代入(1)
5x+1/3=2
5x=5/3
x=1/3
y=-1
答
5x-1/3y=2 ,.(1)
5x+2/3y=1 .(2)
(2)-(1) y=-1
带入（1）得：5x+1/3=2
x=1/3