Graph the following function f(x). Estimate the intervals on which the function is increasing or decreasing and any relative maxima or minima. f(x) = x+2x-8 Determine on which interval(s) f(x) is decreasing. Select the correct choice below and, if necessary, fill in the answer box to complete your choice. O A. The function f is decreasing on the interval(s) (Type your answer in interval notation Use a comma to separate answers as needed.) O B. There is no interval on which the function f(x) is decreasing. Determine the relative maxima or minima. Select the