The graph below shows a company's profit f(x), in dollars, depending on the price of pens x, in
dollars, being sold by the company:

Part A: What do the x-intercepts and maximum value of the graph represent? What are the
intervals where the function is increasing and decreasing, and what do they represent about the
sale and profit?

Part B: What is an approximate average rate of change of the graph from x = 3 tox-5, and what
does this rate represent?