Find the open intervals where the function f(x) - - 3x + 18x + 172x - 8 is concave upward or concave downward. Find any inflection points Select the correct choice below and, if necessary, fill in the answer box to complete your choice O A. The function has a point of inflection at (Type an ordered pair using integers or fractions Simplify your answer, Use a comma to separate answers as needed ) O B. The function does not have an inflection point. Select the correct choice below and, if necessary, fill in the answer box to complete your choice O A. The function is concave upward on the interval(s) (Type your answer in interval notation. Use integers or fractions for any numbers in the expression. Simplify your answer Use a comma to separate answers as needed) O B. The function is never concave upward Select the correct choice below and, if necessary, fill in the answer box to complete your choice. O A. The function is concave downward on the interval(s) (Type your answer in interval notation. Use integers or fractions for any numbers in the expression. Simplify your answer. Use a comma to separate answers as needed ) O B. The function is never concave downward