Construct Function to Model Linear Relationship

• C = 30 + 0.50m

• C = 30m + 0.50

• C = 30 + 50m

• C = 0.50 + 30m

Tags

CCSS.8.F.B.4

• A

• B

• C

• D

A rental car company offers a rental package for a midsize car. The cost comprises a fixed $30 administrative fee for the cleaning and maintenance of the car plus a rental cost of $35 per day.

Using 𝑥 for the number of days and 𝑦 for the total cost in dollars, construct a function to model the relationship between the number of days and the total cost of renting a midsize car.

• 𝒚 = 35𝒙 + 30

• 𝒚 = 30𝒙 + 35

• 𝒚 = 35 + 30𝒙

• 𝒚 = 30 + 35𝒙

A shipping company charges a $𝟒. 𝟒𝟓 handling fee in addition to $𝟎. 𝟐𝟕 per pound to ship a package. Using 𝒙 for the weight in pounds and 𝒚 for the cost of shipping in dollars, write a linear function that determines the cost of shipping based on weight.

The same company is advertising a deal on compact car rentals. The linear function 𝒚 = 𝟑𝟎𝒙 + 𝟏𝟓 can be used to model the relationship between the number of days, 𝒙, and the total cost in dollars, 𝒚, of renting a compact car.

What is the fixed administrative fee?

• The administrative fee is $15

• The administrative fee is $30

• The administrative fee is 15/30

• The administrative fee is 30/15

What is the rental cost per day?

• It costs 30/15 per day to rent the compact car.

• It costs $15 per day to rent the compact car.

• It costs 15/30 per day to rent the compact car.

• It costs $𝟑𝟎 per day to rent the compact car.

Recall that Lenore was investigating two wireless access plans. Her friend in Europe says that he uses a plan in which he pays a monthly fee of 𝟑𝟎 euro plus 𝟎. 𝟎𝟐 euro per minute of use. Let 𝒙 represent minutes of use and 𝒚 represent the total monthly cost in euro. Construct a linear function that determines the monthly cost based on minutes of use.

• 𝒚 = 𝟑𝟎 + 𝟎. 𝟎𝟐𝒙

• 𝒚 = 𝟑𝟎𝒙 + 𝟎. 𝟎𝟐

• 𝒚 = 𝟑𝟎 + 𝟎. 𝟎𝟐𝒙

• 𝒚 = 𝟎. 𝟎𝟐 + 𝟑𝟎𝒙

• (750, 45)

• (45, 750)

• (36,000, 750)

• (750, 36,000)

Kelly wants to add new music to her MP3 player. Another subscription site offers its downloading service using the following: 𝐓𝐨𝐭𝐚𝐥 𝐌𝐨𝐧𝐭𝐡𝐥𝐲 𝐂𝐨𝐬𝐭 = 𝟓. 𝟐𝟓 + 𝟎. 𝟑𝟎(𝐧𝐮𝐦𝐛𝐞𝐫 𝐨𝐟 𝐬𝐨𝐧𝐠𝐬). Let 𝒙 represent the number of songs downloaded and 𝒚 represent the total monthly cost in dollars. Construct a function to model the relationship between the number of songs downloaded and the total monthly cost.

• 𝒚 = 𝟓. 𝟐𝟓 + 𝟎. 𝟑𝟎𝒙

• 𝒚 = 𝟎. 𝟑𝟎 + 𝟓. 𝟐𝟓𝒙

• 𝒚 = 𝟓. 𝟐𝟓𝒙 + 𝟎. 𝟑𝟎

• 𝒚 = 𝟎. 𝟑𝟎𝒙 + 𝟓. 𝟐𝟓

Which of the following is the function rule that describes the number of items, f(n), used to construct the pattern in terms of the term number, n.?

• f(n) = 1 + 4n

• f(n) = 4 + n

• f(n) = 1 + 5n

• f(n) = 5 + 4n