Question

2元一次方程 2(x y)-(x-y)=3 x y-2(x-y)=1

Answer 1

2(x+y)-(x-y)=3……① (x+y)-2(x-y)=1……②

整理得到：x+3y=3 -x+3y=1

两个方程相加得：6y=4,解得：y=2/3

把y=2/3代人x+3y=3中,x+2=3,解得：x=1

∴{x=1 y=2/3