x=3-y-z,从而3-y-z+2y+3z=3+y+2z=62x+y+2z=6-2y-2z+y+2z=6-y= 5 y=1;x=2-z
有3+y+2z=6得4+2z=6 z=1从而x=1
即x=y=z=1