2x+3Y=-5 x+3y=-7 x-y=3

问题描述:

2x+3Y=-5 x+3y=-7 x-y=3

2x+3Y=-5①
x+3y=-7②
x-y=3③
②- ③4y=-10y=-2.5
把 y=-2.5带入③得x=0.5
把 x=0.5带入①得Y=-2