Austin is comparing the prices of two truck rental companies. company a charges $4 per hour and an additional $70 as service charges. company b charges $5 per hour and an additional $60 as service charges. part a: write and equation to represent each conpanys 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. part b: which company would charge less for renting a truck for 6 hours? justify your answer. part c: how much money is saved by using the services of company b instead of company a to rent a truck for 7 hours?