Consider the function f(x) = 9x + 72 ln(x) a. State the intervals of a where f(x) is concave up. [use exact values, no decimals] b. State the intervals of a where f(x) is concave down. [use exact values, no decimals] c. Identify any inflection points on the graph of f(x) as ordered pairs. [you may use decimals here, place commas between any ordered pairs.]