The solution of the system of equations whose augmented matrix 1112123131-54 is

1112123131-54~1112012-10-2-8-2   R2→R2-R1, R3→R3-3R1                      ~10-13012-100-4-4     R1→R1-R2, R3→R3+2R2                      ~40016020-600-4-4      R1→4R1-R3, R2→2R2+R3 ⇒the given system is equivalent to 4x=16, 2y=-6 and -4z=-4. ⇒x=4, y=-3 and z=1