Question

 Resolva o sistema
 x + 2y - 3z + w = 2 
5x + 4y - 13z - w = 0 
- 2x + 2y + 4z + 4w = 6 

Answer 1

[x + 2y - 3z + w = 2    .(-2)
[5x + 4y - 13z - w = 0
  
[-2x - 4y + 6z - 2w = -4
[5x + 4y - 13z - w = 0

[-2x + 0 + 6z - 2w = -4        .(5)
[5x + 0 -13z - w = 0            .(2)

[-10x + 30z - 10w = -20       
[10x - 26z - 2w = 0            .(-5)

[0 + 30z - 10w = -20
[0 + 130z + 10w = 0
------------------------------
160z = -20
z = 160/-20
z = 8