Could you please show me how to do this?

It says to use the elimination method.

2x-y+2z=-7
-x+2y-4z=5
x+4y-6z=-1

2 answers

http://library.thinkquest.org/C0110248/algebra/simelimination.htm
I know how to use the elimination method, I just get really confused when there's three lines and three variables.