I don’t understand this question I have not learned this yet and we are in quarantine lol

If f(x)=2x-6 and g(x)=3x+9, find (f-g)(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.

Given the following linear function sketch the graph of the function and find the domain and range. ƒ(x) = -5x + 4