Score on last try: 0.25 of 1 pts. See Details for more. > Next question You can retry this question below Use the four-step definition of the derivative to find f'(x) if f(x) = 7x3 - 9. f (a t h) = f (act h) - f(2) = f( th) - f(2) h f'(a) = 21x2 Check