2 Consider the function f(x) = x + 6x 3 (c) Give the intervals of increase and decrease of f (x). Note: Use the letter U for union. To enter o, type infinity with a lower case i. If the function is never increasing or decreasing, enter NA in the associated response area. increasing: decreasing: 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 . f( f( )= 0 I E is a local maximum. is a local minimum. (e) Give the intervals of concavity of f (x). Note: Use the letter U for union. To enter , type infinity with a lower case i. If the function is never concave upward or concave downward, enter NA in the associated response area. concave upward: concave downward: (f) Give the inflection points of f (x). Enter your answers in increasing order of the x-coordinate. If there are less than two points of inflection, enter NA in the remaining response areas. Include a multiplication sign between symbols. For example, a T. ( A .) )