x=3y=-1z=0过程啊3x+2y+z=7①2x+3y+4z=3②x+4y+6z=1③2+3得3x+7y+10z=4④4-1得5y-9z=-3⑤3*5得5x+20y+24z=5⑥6-2-1得15y+19z=-5⑦7与5组成方程组15y+19z=-55y-9z=-3解得：x=3y=-1z=0