A car rental agency charges ​$35

per day to rent a car and ​$14.95
per day for a global positioning system​ (GPS). Customers are charged for their full tank of gas at ​$3.40
per gallon. A car has a 19
gallon tank and a GPS.
a) Write a function rule for the total bill b as a function of the days d the car is rented.
​b) What is the bill for a 9 day​ rental?

What's the trouble? Just write down what they told you:

b = 3.40*19 + (35.00+14.95)d

Assuming that the person has to completely refill an empty tank:

35d + 19.95d + 19*3.40 = b

a) To write a function rule for the total bill (b) as a function of the number of days (d) the car is rented, we need to consider the charges for the car rental, GPS, and gas.

- The car rental charge is $35 per day, so the total car rental charge for d days would be 35d.
- The GPS charge is $14.95 per day, so the total GPS charge for d days would be 14.95d.
- The gas charge is $3.40 per gallon, and the car has a 19 gallon tank. So, the total gas charge would be 3.40 * 19.

Adding up all these charges, the function rule for the total bill (b) as a function of the days rented (d) can be written as:
b(d) = 35d + 14.95d + (3.40 * 19).

b) To find the bill for a 9-day rental, we can plug in d = 9 into the function rule we just derived:
b(9) = 35 * 9 + 14.95 * 9 + (3.40 * 19)
= 315 + 134.55 + 64.60
= $514.15.

Therefore, the bill for a 9-day rental would be $514.15.