Arlene is comparing the prices of two truck rental companies. company a charges $7 per hour and an additional $30 as service charges. company b charges $8 per hour and an additional $40 as service charges.

part a: write an equation to represent each company's total charges for renting a truck for a certain number of hours. for both equations (one for company a and one for company b), define the variable used. (4 points)

part b: which company would charge less for renting a truck for 8 hours? justify your answer. (3 points)

part c: how much money is saved by using the services of company a instead of company b to rent a truck for 2 hours? (3 points)