5x+3y-z=0……① 5x-3y+z=-4……② 10x+y+2z=-5 2/3……③①+②得,10x=-4 x=-0.4①×2+②得,20x+7y=-52/3……④把x=-0.4代入④得,-8+7y=-52/3,y=-28/3把x=-0.4 y=-28/3代入①得,z=-30∴x=-0.4 y=-28/3 z=-30
x=-2/5 y = -1/21 z=-15/7
x=-4/10,y=1/3,z=-1