1. Use the Gauss-Jordan elimination process on the following system of linear equations to find the value of z.
-x+y+2z=20
x-4y+4z=13
-2x-6y-3z=-10
2. Use the Gauss-Jordan elimination process to solve the system:
3x+y=2
-6x-2y=-4
12x+4y=8
3. Use the Gauss-Jordan elimination process to solve the following system:
24x-18y+9z=12
-8x+6y-3z=-4