How do I solve this? This is confusing.

Question

Solve the system using matrices.

-3x - y - 2z = -389x + 9z = 1172y + z = 16

Answer 1

Here is a Gauss Jordan calculator
http://www.gregthatcher.com/Mathematics/GaussJordan.aspx
-3 -1 -2 16
-389 0 9 16
0 1172 1 16