For this case, the first thing we must do is define variables. We have then: n: number of journals. We now write the equation for the profits. We have then: P (n) = (6-1.50) n - 600 Rewriting: P (n) = 4.50n - 600 Answer: An equation that represents the profit function of the newsstand is: P (n) = 4.50n - 600