Answer: 2y - 20z = -16
Explanation:
6(2x+y-3z) = 5(6)
=> 12x + 6y- 18z = 30
3(2x + 3y + z) = 13(3)
=> 6x + 9y + 3z = 39
Now minus the top equation from the bottom two:
12x + 6y - 18z = 30
6x + 9y + 3z = 39
6x - 5y - z = 7
12x + 6y - 18z = 30
12x + 4y + 2z = 46
Minus top from bottom:
2y - 20z = -16