x+2y-3z=8①2x+y+2z=5②x+3y-z=7③①-②得-y-4z=1④①*2-②得3y-8z=11⑤④*2-⑤得-5y=-9y=9/5把y=9/5带入④得z=-1/2把y=9/5,z=-1/2带入①得x=-21/5所以x=-21/5y=9/5z=-1/2
依次编号为① ② ③式,①-②×2得-3x-7z=-2 ④,③-②×3得-5x-7z=-8 ⑤④和⑤式联立得x=3,z=-1结果代入①得y=1