Education Technology

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

Published on 06/09/2008

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 use the guess-and-check strategy, manipulate the values of the slope and y-intercept to determine the line of best fit.

Before the Activity

  • Set up the Transformation Graphing on the calculator using the TI Connect™ software
  • See the attached PDF files for detailed instructions for this activity
  • Print pages 1 - 8 from the attached activity PDF file for the class
  • During the Activity

    Distribute the printed pages to the class.

    Follow the Activity procedures:

  • Plot graphs for the linear equation y = mx + b on the calculator and observe how the graph changes with variations in m and b values
  • Write an hypothesis on the effect of m and b on the graph of a line
  • Start the Transformation Graphing Application and graph the equation y = Ax + B
  • Set the starting values for the coefficients and the increment and observe the change in the coefficients.
  • Compare the results with the hypothesis
  • Using the hypothesis, identify graphs of equations and answer questions; verify using the calculator


  • Prepare a scatter plot showing the relationship between the population and number of licensed drivers; identify the independent variable and the pattern in the relationship
  • Estimate the values of the slope and y-intercept for the linear model
  • Use the estimates to graph lines; adjust values of the coefficients to obtain a reasonable model that fits the data
  • After the Activity

    Students' answer questions on the homework page.

    Review student results:

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