Answer step by step.

6. For the function f(x) = 3x4 + 8x3 - 18x2 + 5, nd the following: a) The critical numbers. b) The open intervals where the function is increasing. 0) The open intervals where the function is decreasing. 7. The total prot P(x) in thousands of dollars from the sale of x units of a certain prescription drug is given by P(x) = |n(x3 + 3x2 + 72x + 1)for x in the interval [0,101. a) Find the total number of units that should be sold to maximize the total prot. b) What is the maximum prot