f(x) = 22x
For car B:
After 4 gallons, total mileage is 4 x 22 = 88 miles
After 9 gallons, total mileage is 9 x 22 = 198 miles
After 15 gallons, total mileage is 15 x 22 = 330 miles
In comparison to Car A after 4 gallons
Car B > Car A
88 > 78
After 9 gallons:
Car B > Car A
198 > 171
After 15 gallons:
Car B > Car A
330 > 285
Therefore Car B has a better gas mileage. Car B can travel further in miles in the same amount of fuel as Car A can.
I hope I have explained this well to you,
Have a great day