Modelling with Linear Functions

 In order to join an online learning community, there is a $20 startup fee and a $5 monthly fee. Write an equation in slope-intercept form that models this situation.

• y = 20x + 5
• y = 5x +20

For babysitting, Nicole charges a flat fee of $3, plus $5 per hour. How much money will she make if she babysits 5 hours?

• $28
• $20
• $25
• $15

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

• 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

The GPA of a student can be predicted using the equation
y = 1.4 x + 1.4  where x is the hours the student spends studying.  How many hours did a student spend studying if they have a GPA of 4.2?

• 4
• 3
• not enough information
• 2

A 7-inch candle burns at a rate of 2-inches per hour. Which equation represents the relationship between y, the height of the dandle in inches, and x, the number of hours the candle burns?

• y=2x+7
• y=-2x+7
• y=2-7x
• y=7x+2

Charlie rented a moving truck. He paid a daily fee plus a per-mile fee to rent the truck. The equation below represents the daily amount Charlie paid for the truck if he drives it x miles.
y=0.5x+10
What does the slope of the graph of this equation represent?

• The daily fee for the moving truck
• The per-mile fee for the moving truck
• How much Charlie paid for the truck
• The number of miles he drove

• The amount of money Colby started with
• How much the amount grows each year
• The number of years the money is in the savings account
• The amount in the account after 10 years

Which situation can be represented by y=12x-4?

• The number of eggs, y, in x dozen eggs for sale after 4 dozen eggs are sold
• The cost, y, of buying x movie tickets that sell for $8 each
• The cost, y, after a $4 discount, of buying x T-shirts that sell for $12 each
• The number of inches, y, in an x-foot-tall tree after cutting off 4 feet

• The new graph would have a y-intercept at 80.
• The new graph would be steeper than the original graph.
• The new graph would be less steep than the original graph.
• The new graph would have a y-intercept at 8.

• The number of cookies the presenter had before making any presentations
• The number of cookies the presenter gave away during every presentation
• The number of presentations the presenter made per hour
• The number of presentations the presenter made before running out of cookies