f(x) = x + 15^(2/3)

(c) Give the intervals of increase and decrease of f (a). Note: Use the letter U for union. To enter oo, type infinity with a lower case i. If the function is never increasing or decreasing, enter NA in the associated response area. increasing: decreasing: (d) Give the local maximum and minimum values of f (a). Enter your answers in increasing order of the x-value. If there are less than two local extrema, enter NA in the remaining response areas and the corresponding drop-down menu. Include a multiplication sign between symbols. For example, a . IT. is a local maximum. 0 is a local minimum.{e} Give the intervals of concavity of f{a:). Note: Use the letter U for union. To enter 00, type innity with a lower case i. If the function is never concave upward or concave downward, enter NA in the associated response area. concave upward: ' NA 'n IE concave downward: ' 'I la