Question 23 0/1 pt ) 100 99 0 Details Consider the function f(x) = 3x + 9x . For this function there are four important open intervals: ( - 0o, A), (A, B), (B, C), and (C, oo) where A, and C are the critical numbers and the function is not defined at B. Find A and B and C For each of the following open intervals, tell whether f(x) is increasing (type in INC) or decreasing (type in DEC). ( - 00, A): (A, B): (B, C): (C, 0.): Question Help: Message instructor Submit