Consider f(x) = 3x3+8x Determine the intervals on which f is decreasing. of is decreasing on: of is decreasing nowhere. Determine the intervals on which f is increasing. of is increasing on: of is increasing nowhere. Determine the value and location of any local minimum of f. Enter the solution in (x, f(x)) form. If multiple solutions exist, use a comma-separated list to enter the solutions. of has a local minimum at: of has no local minimum. Determine the value and location of any local maximum of f. Enter the solution in (x, f(x)) form. If multiple solutions exist, use a comma-separated list to enter the solutions. of has a local maximum at: of has no local maximum.