Answer:
x = 3, y = -1, z = -4
Explanation:
2x + y - z = 9 (1)
- x + 6y + 2z = -17 (2)
5x + 7y + z = 4 (3)
(3) + (1)
7x + 8y = 13 (4)
2 × (1)
4x + 2y - 2z = 18 (5)
(5) + (2)
3x + 8y = 1 (6)
(4) - (6)
4x =12
x = 3
substitute x = 3 in (6)
9 + 8y = 1
8y = -8
y = -1
substitute x = 3 and y = -1 in (1)
2 × 3 + (-1) - z = 9
6 - 1 - z = 9
5 - z = 9
z = 5 - 9
z = -4