x-y-z=-1 (1)
3x+5y+7z=11 (2)
4x-y+2z=-1 (3)
(1)×7+(2)得 10x-2y=4 即 5x-y=2 (4)
(1)×2+(3)得 6x-3y=-3 即 2x-y=-1 (5)
(4)-(5)得 3x=3 x=1
代入(4)得 y=3
代入(1)得 z=-1
x-y-z=-1 (1)
3x+5y+7z=11 (2)
4x-y+2z=-1 (3)
(1)×7+(2)得 10x-2y=4 即 5x-y=2 (4)
(1)×2+(3)得 6x-3y=-3 即 2x-y=-1 (5)
(4)-(5)得 3x=3 x=1
代入(4)得 y=3
代入(1)得 z=-1