Question

I have a few questions I need help with!

1. Solve the system by triangularizing the augmented matrix and using back substitution. If the system is linearly dependent, give the solution in terms of a parameter.
-3x+y-z=-4
6x-2y+2z=8
-12x+4y-4z=-16

2. Solve the system by triangularizing the augmented matrix and using back substitution.
6x=y-4
3y=-13-7x

3. What row operation would produce zero beneath the first entry in the diagonal?
1 2 | -1
8 -2 | -2