PLEASE ANSWE

Mr. Kinman is planning to take his study group on a field trip to an amusement park. The regular cost is $18.50 per person. There is a party special that costs $15 per person with an additional $28 fee for a private room where students can eat lunch. Mr. Kinman is trying to decide if he should use the regular price or the party special.

Write an equation in slope-intercept form (y=mx+b) to show the total cost of the regular price with x people, where x = number of students in the study group and y = the total cost.