What do you need help on.
C(x) = 5x + 2
This is because at 1 hour it only cost 7 dollars, so it should only have 2 added to the end.
total distance travelled=72+69=141
time taken in hours for journey= (48/60)h + (69/60)= 1.95 h
average speed=141km/1.95h= 72.3km/h (3 sf)
They are inverses.
The easiest way to solve this is to take the g(x) equation and switch the g(x) with the x. Then solve for your new g(x). Since it looks just like f(x) after doing that, it is an inverse.