A local clothing store gives a discount of $15 off any purchase of $50 or more in the month of August. This can be represented by the function f(x) = x-15. This same store gives a 15% discount to teachers on the third week of every month. This can be represented by the function g(x) = 0.85x. Reed is a teacher and decides to shop at this store in the third week of August. Select all of the following that could be used to calculate what Reed will pay that day if he spends $50 or more.