Construct Function to Model Linear Relationship

Write an equation for the cleaning cost, y, for the number of hours, x. Put in y = mx + b form.

• y = 12x + 20

• y = 20x + 8

• y = 8x

• y = 8x + 20

What is the cleaning cost per hour (slope)? (hrs are the x values)

• 8

• 20

• 12

• 28

Write an equation for the line that represents Penelope's distance, y, from soccer practice after x minutes. Use y = mx + b.

• y = -110x + 2480

• y = 110x + 2000

• y = -110x +2040

• y = 5x +1930

The trade-in value, V, of a certain model of automobile can be determined using the function V(x)=25000-0.25x, where x is the mileage. Which of the following statements is the best interpretation of the slope?

• The value of the car increases as the mileage increases.

• The selling price of the car when it is new is $25,000.

• The trade-in value of the car decreases $4 for every additional mile driven.

• The trade-in value of the car decreases $1 for every additional 4 miles driven.

Printer ink costs $18.99 per cartridge. The company that sells the ink cartridges charges a flat rate shipping fee of $7.95, no matter the number of cartridges purchased in a single order. Which linear function models the total cost, t, for a single order of c cartridges?

• c = 26.94t

• c = 18.99t + 7.95

• t = 26.94c

• t = 18.99c + 7.95

A new discount cell phone service charges $55 a month plus $15.00 for every line on the plan. Choose the linear function that represents the relationship between the number of lines (x) and the cost of the plan (y).

• y = 70x

• x = 70y

• y = 55 + 15x

• x = 55 + 15y

Printer ink costs $16.89 per cartridge. The company that sells the ink cartridges charges a flat rate shipping fee of $4.25, no matter the number of cartridges purchased in a single order. Which linear function models the total cost, t, for a single order of c cartridges?

• c = 21.14t

• c = 16.89t + 4.25

• t = 21.14c

• t = 16.89c +4.25

The initial weight of a container is 6.2 pounds. As water is added to the container, the weight increases at a rate of 0.6 pounds per minute. Which function models the weight of the container as a function of time?

• f(t)=0.6t+6.2

• f(t)=t+6.8

• f(t)=6.2-0.6t

• f(t)=6.2t+0.6

Ted's Taxi service charges a $5 pick up fee plus $2 per mile. Which function describes the situation?

• y=5x+2

• y=2x-5

• y=5x-2

• y=2x+5

A moving company charges $90 to rent a truck for 4 hours or $150 to rent a truck for 8 hours. What equation can be used to model the cost of renting the truck per hour?

y = ​ (a)   ​ (b)   ​ (c)  

• 15x

• 60x

• +

• -

• 30

• 4

• 15

• 60

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