Definition: A linear inequality in 1 variable is a linear equation in 1 variable in which the "=" has been replaced by an inequality.

Regulation: The solution set of a linear inequality is an interval on the number line bounded by the point solution of the corresponding linear equation. (This interval includes this point only if inequality includes the equals sign, i.e. is not a strict inequality).
Examples of linear inequalities in 1 variable:   \bbox[border:1px #990000 dotted,1pt]{x>3}    \bbox[border:1px #990000 dotted,1pt]{5x-3 \leq 2}    \bbox[border:1px green dotted,1pt]{3s<-2}
InterActivity    Directions for InterActivity  Menu to all interactivities with Inequalities on the Number Line

Goal: Graph an inequality on the number line.

1. Type or paste an inequality in x in the box. Hit Enter. Values on the red arrow makes the inequality "true".

Other examples:  x+3≤5,  2x+1>4,  3>=4x/5-11/5

2. To change the view, click on the Move tool Move Graphics View and then click and drag the number line as desired.

• An open endpoint means NO "=" in the inequality.

3. Find the value of any point under the red arrow. Substitute this value for x into the inequality. The inequality should be "true".

4. Find the value of any point NOT under the red arrow. Substitute this value for x into the inequality. The inequality should be "false".

• To start over, enter a new inequality and hit Enter.

Inequality:     Copy & paste samples: 4>x  -x≥2  1>4+x  3x-4≤2-x  
Sorry, the GeoGebra Applet could not be started. Please make sure that Java 1.4.2 (or later) is installed and active in your browser (Click here to install Java now)
Many thanks to mathmagic and piman!      LFS , Created with GeoGebra

Related Topics

Global Graphing Linear Inequalities in 1 Variable
Brief InterActivities for graphing inequalities on the number line
Grade 7th and up (must know how to plot a point on the number line)
Strand Algebra and Functions AF at Math247
Standard Algebra & Functions 7 4.1   ACT EE 24-37   ACT GR 24-27
Keywords linear, inequality, number line, interval, 1 variable, algebra, dynamic, freeware, applet, offline, online
Comments Hopefully a reverse interactivity coming soon.
Credits David Cox for asking; MathMagic and Piman of the GeoGebra forum for their help!
Download February 2009 completely offline and school (webstart)
Author LFS - contact
Type Freeware - Available for Offline and Online Use - Translatable (html)
Use Requires sunJava player

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Page last modified on July 20, 2009, at 08:49 AM