Education Technology

Investigating Slope and Y-Intercept

Published on 06/09/2008

Activity Overview

In this activity, students investigate the effect of change in parameters m (slope), and b (y-intercept) on the graph of the equation y = mx + b.

Before the Activity

  • See the attached PDF file for detailed instructions for this activity
  • Print pages 1 - 7 from the attached PDF file for your class
  • During the Activity

    Distribute the pages to the class.

    Follow the Activity procedures:

  • Graph the equation y = mx for m = 1
  • Change value of slope m to 2, 3, and 4, and graph the equations
  • Observe that greater the value of m, the steeper the graph
  • Change value of m to 1/2, 1/3, and 1/4 and sketch the graph of the lines
  • Observe that as the value of m becomes smaller the graph becomes less steep
  • Change slope value to -1, -2, and -1/2 and graph the lines
  • Note that graphs with negative slopes all decrease as x increases and as the value of m approaches zero, the graph becomes less steep
  • Change y-intercept to 2, -1, and 5 and graph the lines
  • Observe that the y-intercepts and the value of b are the same
  • After the Activity

    Students complete the Analysis questions.

    Review student results:

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