8)

The total differential of f (x, y) = x3 + 3 - 6 xy is O df = 3 (x2 - 2y)+ (12 -2x)] O none of the choices Odf = 3 (x2 - 2y) dy+ (1 - 2x) dx O df = 3 (x2 - 2y) dx+ (12 - 2x) dy O df = 3 (x2 - 2y) dx - (12 - 2x) dy