(1 pt) Consider the function f(x) = 9x + 8x . For this function there are four important intervals: (-co, A], [A, B), (B, C), and [C, co) 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 intervals, tell whether f(x) is increasing (type in INC) or decreasing (type in DEC). (-00, A]: [A, B): (B, C]: [C, co)