At an airport it costs 7 dollars to park for up to one hour and five dollars per hour for each additional hour. let x represent the number of hours parked . write the function function that models the cost of parking x hours, where x is an integer greater than one

I came up with 7+5(x-1)
7 is a fixed one time cost. 
5(x-1). x-1 because you have already charged $7 for the first hour.

Checking to make sure it is correct
so if a person stays 1 hour
7+5(1-1)
7+5(0) = 7     
This answer makes sense because they get charged $7 the first hour

so say they stay 3 hours
7+5(3-1)
7+5(2) = 17
This answer makes sense because they get charges $7 for the first hour and $5 for the other 2. so 7+5+5=17.

we can see that the function works

Idrk but i think u should figure out the n dia n then the units it will make it way more easier