Anewsstand spends $600 a month on rent and electricity, and it spends $1.50 for each magazine that it sells. the newsstand charges $6 for each magazine. if n is the number of magazines, which equation represents the profit function of the newsstand?

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
 
 An equation that represents the profit function of the newsstand is:
 P (n) = 4.50n - 600