X-Y+3Z=4 2x+y-2=1 3x-2y +z=-3

2x - 2y + 6z = 8
2x + y - z = 1
____________-
-3y + 7z = 7

3x - 3y + 9z = 12
3x - 2y + z = -3
____________-
-y + 8z = 15
y = 8z - 15

-3y + 7z = 7
-3(8z-15) + 7z = 7
- 24z + 45 + 7z = 7
17z = 38
z = 38/17

y = 8z - 15 = 8(38/17) - 15 = 304/17 - 15 = 49/17

x = 4 + y - 3z
x = 4 + 49/17 - 3(38/17)
x = 3/17