Solve this system
5x – 4y + 2z = 21
-x - 5y + 6z=-24
--x – 4y + 5z =-21
O x = 5, y = -1, z = -4
0 x = 1, y = 5, z = -4
O x=-5, y = 1, z = -4
O x = -4, y = -1, z = 5