若x和y互為相反數,則方程組{3x+2y-z=1,2x-y+2z=8的解為

若x和y互為相反數,則方程組{3x+2y-z=1,2x-y+2z=8的解為

x=-y代入3x+2y-z=1可得-3y+2y-z=1 z=-y-1把x=-y z=-y-1代入2x-y+2z=8解得y=-2
代入x=-y解得x=2把y=-2代入z=-y-1解得z=-3