Augmented matrix problem?

Question

how do you answer this problem using augmented matrix?

x - 2y - z= 3

x + y + z= 4

x - 3y - z=4

Answer 1

Greetings,

[1 -2 -1 | 3]

[1 1 1 | 4]

[1 -3 -1 | 4]

[1 -2 -1 | 3]

[0 3 2 | 1] R2 - R1

[0 1 0 | -1] R1 - R3

[1 0 -1 | 1] R1 + 2*R3

[0 1 0 | -1] R3 <-> R2

[0 0 2 | 4] R2 - 3*R3

[1 0 0 | 3] R1 + (1/2)*R3

[0 1 0 | -1]

[0 0 1 | 2] (1/2)*R3

The answer is x = 3, y = -1, z = 2

Regards