Solve the following set of homogeneous equations by Gauss-Jordan reduction of the matrix of coefficients (without the column of zeros from the right-hand side.

5x+5y-5z=0

3x+4y-7z=0

2y-8z=0

-2y-3y+6z=0

I know to do Gauss-Jordan reduction for three equations, but not four. How do I do this - I'm pretty confused