I need help answering this long question...

Consider the function f(x) - - 2x3 + 36x2 - 120x + 9. For this function there are three important open intervals: ( - 0o, A), (A, B), and ( B, co) where A and B are the critical numbers. Find A and B For each of the following open intervals, determine whether f (x) is increasing or decreasing. ( - 0o, A): Select an answer (A, B): Select an answer (B, .): Select an answer Using the First Derivative Test, we can conclude: at x = A, f(a) has a Select an answer C at x = B, f(a ) has a Select an answer C Question Help: DVideo