Constructing Linear Functions

Construct a linear model for the graph.

Construct a linear model for the table.

What variable is the slope in y = mx + b?

• y

• m

• x

• b

What variable is the y-intercept in y = mx + b?

• y

• m

• x

• b

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

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

The diagram shows a linear function of g. What is the value of k.

• 5

• 4

• 7

• 8

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 pond in Luke's neighborhood has a depth of 81.6 inches. During the dry season, the pond loses an average of 0.02 inches of water each day. Luke wrote the function below to represent the depth of the pond in inches x days after the dry season begins. Explain Luke's error and rewrite the function correctly.

• f(x) = -0.02(x + 81.6)

• f(x) = -0.02x + 81.6

• f(x) = -0.02x - 81.6

• f(x) = -0.02(x - 81.6)