If you are done:Take the algebra book from

under your seat.

Begin to read about functions:Page 46

September 17, 2014

Can I create equations in two variables to represent the relationship between two

variables?

Writing Functions

You buy a printer for $80 and then pay $15 for each ink cartridge that you use. A

function relating the cost, Y (in dollars), of operating the printer

to the number of cartridges used, x:

Y = 15+ 80.

Domain: Set of input values

Range: Set of output values

Let’s talk about the parts of this function

Complete the table to represent the total cost for 0 to 4 cartridges.

Number of cartridges

Total Cost

0

1

2

3

4

Graph the function from the tableCHOOSE A REASONABLE SCALE

What is the initial value of the cost function? What does it represent?

What number of cartridges corresponds to the initial cost?

Define the domain. Define the range. What would the total cost be if you

purchased 17 cartridges? How would your cost change if the printer

cost $90?

Let’s analyze this function

Andrea receives a $40 gift card to use a town pool. It costs her $8 per visit to swim. A function relating the value of the gift card to the number of visits.

Write an function to represent this situation.

Make a table of values.

Graph the function

Now you try:

What is the initial value? (1 talk to 2)

What is the difference between a given card value and the previous card value? (2 talk to 1)

Identify the domain and the range of the function using set notation (1 talk to 2)

Is it possible for the card to have a value of $35? Why or why not? (2 talk to 1)

Turn and talk

Work on Explore 1 in your groups.

Be ready to share.

On Your Own: