Question

x+y+z=-1 4x-2y+3z=5 y-z=8-2x

Answer 1

x+y+z=-1 (1)

4x-2y+3z=5 (2)

y-z=8-2x (3)

由(3)得

2x+y-z=8 (4)

(1)+(4)得

3x+2y=7 (5)

(4)×3+(2)得

10x+y=29 (6)

解方程组(5)(6)得

x=3

y=-1

把x=3,y=-1代入(1)得

z=-3

∴x=3

y=-1

z=-3