Consider the equation below. (If an answer does not exist, enterDNE.) f(x) = x3 − 6x2 − 15x + 9 (a) Find the interval on which f isincreasing. (Enter your answer using interval notation.) Incorrect:Your answer is incorrect. Find the interval on which f isdecreasing. (Enter your answer using interval notation.) Incorrect:Your answer is incorrect. (b) Find the local minimum and maximumvalues of f. local minimum value local maximum value (c) Find theinflection point. (x, y) = Find the interval on which f is concaveup. (Enter your answer using interval notation.) Find the intervalon which f is concave down. (Enter your answer using intervalnotation.)
