Solve the simultaneous questions:

(a) x+y+z=-3 (1)(b)x+2y+3z=-14 (1)
x-y-2z=13(2) 2x+3y-z=13 (2)
y-4z=25 (3) 3x-y+2z=-7 (3)

hard to tell which are your groups of equations.