问题呢?求x,y原式=3x+y/2=2x+y+0.4 得y/2=y-x+0.4 y=2y-2x+0.8 0=y-2x+0.8 得y+0.8=2x,代入2x+y+o.4,得2y+1.2=0.5y+0.4+5y/-3得,2y=0.5y+0.4-5/3y-1.22y=-6.5/3y-0.8,2y+6.5/3y=-0.8,12.5/3y=-0.8,y=-0.8/12.5/3.不想算了。。。。。。得数？