Writing Linear Functions

A holiday meal costs $12.50 a person plus a delivery fee of $30. Which equation represents the amount a holiday meal costs, including delivery, for x people?

• y = 12.5x + 30

• y = 12.5 + 30

• y = 12.5 + 30x

Easy Car Rental charges $8.50 an hour plus a rental fee of $25.50. Which equation represents the total charges for x hours?

• y = 8.5 + 25.5

• y = 8.5x +25.5

• y = 25.5x +8.5

Jerry has $20 and makes $7 per hour. Which equation represents the total amount of money Jerry has after working x hours?

• y = 7x + 20
• y = 7 + 20x
• y = 20 + 7

Sonya has $40 in her lunch account and pays $2 each day to eat lunch. Which equation can be used to find the amount of money Sonya has left on her account after x days?

• y = 40 + 2x

• y = 40 - 2x

• y = 2 + 40x

• y = 2 - 40x

Sandra has a $20 itunes gift card and spends $3 each month.  Which equation can be used to find how much money Sandra has on her giftcard after x months?

• y = 3x + 20
• y = 3 + 20x
• y = -3x + 20
• y = -20x + 3

For lunch, Amanda had a hamburger and some potato chips. The hamburger totaled 325 calories and each chip had 12 calories. Write a liner equation to represent the situation.

• y = 12 + 325
• y = 12x  + 325
• y = 325 - 12x
• y = 325x + 12

Which equation shows the number of bottles left after x days?

A family buys a case of water with 48 bottles and drinks 5 bottles per day.

• y = 48x + 5

• y = -5 + 48x

• y = -5x - 48

• y = - 5x + 48

The Roaming Cell Phone Company charges $15.00 per month plus $0.20 per minute of airtime usage.  If Juanita uses x minutes of airtime, what is an equation that can be used to determine her monthly cell phone bill (C)?

• C = 0.20x + 15
• C =15 (0.20x)
• C = 15 + x + 0.20
• C = 0.20 + 15x

The local service center advertises that it charges a flat fee of $50 plus $8 per mile to tow a vehicle. Write an equation that represents the total cost (C) of a service for m miles of towing.

• y = 8x + 50

• C = 50m +8

• y = 50x + 8

• C = 8m + 50

Which of the following situations could be descried by the equation y= -25x + 120

• There are 120 people in the football stadium, and 25 more are entering each hour.
• A plumber charges $25 for a house call and $120 per hour.
• A teacher has 120 students. Her third period has 25 students
• There are 120 gallons of water in a tank. It releases water at a rate of 25 gallons per minute