Factoring the equation gives P(x) = (x - 4)(x - 2)(x + 1)(x + 2).
The graph will begin at x = 0, where P(x) = 16, as this is the y-intercept of the function. From 0 <= x < 2, P(x) > 0. There are break-even points at x = 2 and x = 4, while between them, P(x) < 0. As x increases beyond x = 4, the profit P(x) increases greatly (up to infinity). The section of the graph below x = 0 is meaningless, as the company cannot produce a negative number of laptops.
