Also additional problems are asking for D. Find the intervals where f(x) is concave up and the intervals where f(x) is concave downE. Find the inflection points of f(x) or state that there are none.

All work must be shown for full credit. 1. Let f(x) = x - 9x + 15x + 9. a. (1 pt) Find the critical numbers of f (x) or state that there are none. b. (3 pts) Find the intervals where f (x) is increasing and the intervals where f (x) is decreasing. c. (2 pts) Find the local extrema of f (x) or state that there are none