Answer:
x = - 1, y = 2, z = 1
Explanation:
Given the 3 equations
2x - y + 3z = - 1 → (1)
x + 2y - 4z = - 1 → (2)
y - 2z = 0 → (3)
Add (1) and (3) term by term
2x + z = - 1 → (4)
Multiply (1) by 2
4x - 2y + 6z = - 2 → (5)
Add (2) and (5) term by term
5x + 2z = - 3 → (6)
Multiply (4) by - 2
- 4x - 2z = 2 → (7)
Add (6) and (7) term by term
x = - 1
Substitute x = - 1 into (4)
- 2 + z = - 1 ( add 2 to both sides )
z = 1
Substitute x = - 1, z = 1 into (2)
- 1 + 2y - 4 = - 1
- 5 + 2y = - 1 ( add 5 to both sides )
2y = 4 ( divide both sides by 2 )
y = 2
solution is (x, y, z ) = (- 1, 2, 1 )