Question

-3x-y+2z=-6
2x+y-z=3
x-2y+z=1

Answer 1

Ola Faby

-3x -   y + 2z = -6
 2x +  y -    z = 3
   x - 2y +   z = 1

z = 2x + y - 3
2z = 4x + 2y - 6

-3x - y + 4x + 2y - 6 = -6
x + y = 0

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

x + y = 0
3x - y = 4

4x = 4
x = 1
y = -1

z = 2x + y - 3 
z = 2 - 1 - 3 = -2

S = {(x, y, z), (1, -1, -2)}