Use Gaussian elimination to solve the following systems of linear equations.
2y +z = -8 x+y+z = 6 X
(i) x - 2y — 3z = 0 -x+y+2z = 3 2y - 62 = 12
(ii) 2x−y+z=3
(iii) 2x + 4y + 12z = -17 x