Answer:
We know that the hotel charges 12.5% in taxes (or 0.125 in decimal form).
Then if the initial cost of the hotel, without taxes, is a, the price with taxes will be:
f(a) = a + 0.125*a = 1.125*a
And the hotel also charges a fee of $25 for each day (that is not subject to taxes) then if the total cost, with taxes, is b, the actual cost will be:
g(b) = b + 25.
Then:
a = The cost of the hotel room without sales tax or the resort fee.
f(a) and b= The cost of the hotel room and sales tax, but without the resort fee
g(b) = The cost of the hotel room, with sales tax and the resort fee.