2x+3y+z=11 ①x+y+z=6 ②3x-y-z=-2 ③由①-②得x+2y=5④由②+③得4x=4x=1代入④得1+2y=5y=2把x=1,y=2代入②得1+2+z=6z=3故方程组的解为x=1y=2z=3...