PLEASE HELP! Economics

What is the quadric regression equation that fits these data

5,600 x 10^3 = a) 560 b) 5,000,600 c) 5,600,000 d) 56,000

Tom wants to order tickets online so that he and three of his friends can go to a water park the cost of the tickets is 16.00 per person there is also a 2.50 one-time service fee for ordering tickets online write an expression in term of n that represents the cost for n ordering tickets online