1. Comparing Costs
Investigation 2.3

2. Baxter and Orlando’s Race
The point at which a line crosses the y-axis is called the y-intercept.
What is the y-intercept for Orlando?
What is the y-intercept for Baxter?
(0, 0)
(0,45)
100 80 60
Orlando
Distance (meters) 40
Baxter 20
Time (seconds)

3. Baxter and Orlando’s Race
Writing an equation for each line. Remember D = rt (Distance = rate * time)
The distance , DOrlando, that Orlando walks after t seconds can be represented by the equation DOrlando = 2.5t. Because Orlando walks 2.5 meters per second and started at (0,0).
The distance, DBaxter, that Baxter is from where Orlando started, can be given by the equation, DBaxter = t. Because Baxter started at (0, 45) and walked 1 meter per second [the coefficient for t is 1].

4. Linear Equations
All of the linear equations we have studied so far can be written as: y = mx + b or y = b + mx
The value “b” is the number where the line crosses the y axis. It is the y-intercept.
The m in y = mx + b is called the coefficient of x and mx means m times x.

5. Activity 5
Mrs. Jensen’s class is so excited to be a part of the walkathon that they want everyone who participates to have a special T-shirt.
Cameron did some research and found two different companies we can order the shirts from:
Mighty T
No-Shrink T
You are going to find out which company gives us the best deal on buying T-shirts.