x+y+z=-1 ①
4x-2y+3z=5 ②
2x+y-z=8 ③
③-①:x-2z=9 ④
①*2+②:6x+5z=3 ⑤
④*6-⑤:-17z=51,得z=-3
代入④：x=2z+9=3
代入①：y=-1-x-z=-1
解为x=3,y=-1,z=-3