若x和y互为相反数,则方程组{3x+2y-z=1,2x-y+2z=8的解为

问题描述:

若x和y互为相反数,则方程组{3x+2y-z=1,2x-y+2z=8的解为

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