To solve a system of three linear equations in three variables by the addition method.
Solve by the addition method:
x + 3y + z = 6
3x + y - z = -2
2x + 2y - z = 1
x - 2y - z = 1
x + 3y + z = 16
3x - y - z = 12
2y + z = 7
2x - z = 3
x - y = 3
3x + 4z = 5
2y + 3z = 2
2x - 5y = 8
the answers should be (?,?,?) can someone help me break it down??!?