Question

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

Answer 1

{x+y+2z=-1
{2x-3y+z=1
{3x+4y-z=4
[1. 1 2] 1. 1
[2 -3. 1] 2 -3
[3. 4. -1] 3. 4
D=3+3+16+18-4+2
D=38
[-1. 1. 2] -1. 1
[1. -3. 1] 1. -3
[4. 4. -1] 4. 4
Dx=-3+4+8+24-4+1
Dx=30
[1. -1. 2] 1 -1
[2. 1. 1] 2. 1
[3. 4. -1] 3. 4
Dy=-1-3+16-6-4-2
Dy=-16+16
Dy=0
[1. 1. -1] 1. 1
[2. -3 1] 2 -3
[3. 4. 4] 3. 4
Dz=-12+3-8-9-4-8
Dz=-41+3
Dz=-38
Dx/D=30/38
Dy/D=0/38=0
Dz/D=-38/38=-1