# Activities

• • • ##### Subject Area

• Math: Algebra I: Linear Functions

• ##### Author 9-12

50 Minutes

• ##### Device
• TI-83 Plus Family
• TI-84 Plus
• TI-84 Plus Silver Edition

TI Connect™

• ##### Accessories

TI Connectivity Cable

• ##### Other Materials
This is Activity 1 from the EXPLORATIONS Book:
Exploring Mathematics with the Transformation Graphing Application.
• ##### Report an Issue

How Many Drivers? Investigate the Slope-Intercept Form of a Line

#### Activity Overview

In this activity, students will be introduced to the slope-intercept form of a linear equation. They will recognize the effects of changes in the slope and y-intercept on the graph of a line. Students will use the Transformation Graphing application to find an approximate linear model of the actual data. They will determine the line of best fit on a scatter plot by using the guess-and-check strategy to manipulate the values of the slope and y-intercept.

#### Before the Activity

Install the Transformation Graphing application on the students' graphing calculators using one of these two methods:

• TI-Connect™,  a TI Connectivity Cable, and the Unit-to-Unit Link Cable
• TI-Navigator™  "send to class" feature
• See the attached PDF file for detailed instructions for this activity
• Print pages 1-12 from the attached PDF file for your class
• #### During the Activity

Distribute pages 1-12 to your class.

• Plot graphs for the linear equation using the given values of m and b and observe how the graphs change with variations in m and b
• Write a hypothesis about the effects of m and b on the graph of a line
• Use the Transformation Graphing application to investigate the effects of varying m and b
• Notice that the value of m affects the slope of the line and the value of b affects where the line crosses the x-axis
• Observe the changes in the graph by varying the value of m and b, and compare the results with the hypothesis
• Prepare a scatter plot showing the relationship between the population and number of licensed drivers in selected states
• Estimate the value for the slope and y-intercept of a linear model that represents the data
• Find a line that represents an approximate fit of the data
• Determine the slope and the y-intercept, and compare with the estimated values
• Predict the number of licensed drivers for a given population size and verify the prediction
• #### After the Activity

Students will complete the Worksheet and answer questions.

Review student results:

• As a class, discuss questions that appeared to be more challenging
• Re-teach concepts as necessary