(2^6 x 9^6 ) divided 18^14

If f(x)= 3x+6 which of the following is the inverse of f(x)

Omar is going on a road trip! the car rental company offers him two types of cars. each car has a fixed price, but he also needs to consider the cost of fuel. the first car costs $90 to rent, and because of its fuel consumption rate, there's an additional cost of s0.50 per kilometer driven.

If f(x) = x+8 and g(x) = 4x- 3, find (f+g)(x)