The high school band is selling wrapping paper. it costs $4 each week to advertise the wrapping paper. the band buys each roll of wrapping paper for $2.00 and sells each one for $3.50. write an equation to model the amount of profit, p, the band makes from selling x rolls of wrapping paper in one week.

For this case, the first thing we must do is define variables:
 x: rolls of wrapping paper in one week
 We now write the equation that models the profit of the band.
 We have then:
 P (x) = (3.50 - 2) x - 4
 P (x) = 1.50x - 4
 
 An equation to model the amount of profit, P, the band makes from x rolls of wrapping paper in one week is:
 P (x) = 1.50x - 4