x+z-3=0 ①
2x-y+2z=2 ②
x-y-z=-3 ③
①得x=3-z带入②得6-2z-y+2z=2得y=4
则③得x-4-z=3即x-z=7
①+③得2x=10即x=5,z=-2
所以x=5,y=4,z=-2