If the solutions of the equations ax by = 8, cy BZ = 1, 2bx + CZ = 5 are x = 1, y = - 2, z = - 1, then what is the number of ABC

If the solutions of the equations ax by = 8, cy BZ = 1, 2bx + CZ = 5 are x = 1, y = - 2, z = - 1, then what is the number of ABC

a=2,b=3,c=1