Teaching Algebra with Manipulatives

Using Overhead Manipulatives
Demonstration 2
Graphing y 3x 5 and Other Inequalities
• Prepare a transparency for the graph of y 3x 5. Before
displaying the graph, inform students you are going to graph
y 3x 5. Ask whether the shaded region will be above or
below the graph of the line and why. Above; y is greater than a
value. Display the graph.
• Point out that in this case y is greater than or equal to 3x 5.
Ask what points are included in the graph. all points in the
region above the line and on the line
• Write the following inequalities on a blank transparency. Have
students tell what points would be included in the graph of each
inequality.
Inequality
y 5
y 2x 1
y 1 2 x
Points Included in the Graph of the Inequality
all points below the line y 5
all points below the line y 2x 1 and on the line
all points above the line y 1 2 x
O
y
x
Algebra 1—Chapter 6
• On a blank transparency, write the information shown below.
Ask students to write the inequality.
Inequality
Points Included in the Graph of the Inequality
y 4 all points above the line y 4
y 3x 1
y 4x
all points above the line y 3x 1 and on the line
all points on the line y 4x
© Glencoe/McGraw-Hill 121 Teaching Algebra with Manipulatives