4（x-y-1)=3(1-y)-2,
4x-4y-4=3-3y-2
4x-y=5
y=4x-5 (1)
二分之x+三分之y=2
3x+2y=12 (2)
(1)代入(2),
3x+2(4x-5)=12
11x=22
x=2
y=4×2-5=3
方程组的解为x=2,y=33分之2(x-y)-4分之X+Y=-1,6(X+Y)-4(2X-Y)=16这道题呢??????????????X谢谢3分之2(x-y)-4分之(X+Y)=-1,8(x-y)-3(x+y)=-125x-11y=-12(1)6(X+Y)-4(2X-Y)=16-2x+10y=16-5x+25y=40 (2)(1)+(2),14y=28解得y=2x=2