For the functions f(x) = 3x – 6 and g(x) = 3, (f9) (x) would be equal to:
a) (f9)(x) = 9x2 – 18
b) (f9) (2) = 9x – 18
c) (f9) (2) = x – 2
d) (f9) (x) = 3x – 3