Representing Linear Situations

1. A plant is 5cm tall and growing at a rate of 3cm a month.

• 5 + 3
• 5x + 3
• 5 + 3x

Bob has $150 in his savings account and saves $40 per month.

• 150 + 40
• 40x + 150
• 150x + 40

A holiday meal costs $12.50 a person plus a delivery fee of $30.

• 30 + 12.5x 
• 12.5 + 30
• 12.5 + 30x

Sonia has $40 in her lunch account and pays $2 each day to eat lunch.

• 40 + 2x
• 40 - 2x
• 2 + 40x
• 2 - 40x

Write an expression for the following. Jerry has $20 and makes $7 per hour.

• 7x + 20
• 7 + 20x
• 20 + 7

A fitness club opens with 80 members. Each month the membership increases by 15 members. Which equation represents the relationship between the number of months the club has been opened, x, and the total fitness club membership, y?

• y=15x
• y=15x+80
• y=x+15
• y=80x+15

Easy Car Rental charges $8.50 an hour plus a rental fee of $25.50.

• 8.5 + 25.5
• 25.5 + 8.5x
• 8.5 + 25.5x

Jacob collects hats.  He has 6 hats already, and he collects 2 hats a week.

• y = 2x + 6
• y = 6x + 2
• y = 2x - 6
• y = 6x - 2

At Joe's Clown Car Rental Agency, renting a car costs $35 plus $0.75 for every mile it is driven. 

• y = x(35 + 0.75)
• y = 35x + 0.75
• y = 0.75x + 35
• y = 0.75(x + 35)

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