I am not a mathematics student but have intermediate knowledge because of my engineering background. Recently a student asked me that he is having a problem in displaying graph inequalities in Excel. He had a project to submit. My problem was first to understand what one means by saying “How to graph inequalities number line”. I was in a situation where a software designer, developing a banking software has to know the banking process better than the banker.

I decided to do some research on how to graph inequalities and following is the result.

If you need to graph The equations that are formed by “<=” or “>=” instead of just “=”, are termed as “Graphing inequalities”.

Below are a few examples:

Graph inequalities for one variable and the picture below are self-explanatory. The pictures depict how various conditions of inequalities are represented graphically. Try to understand why some circles are filled with colors and others are not.

2) Equations for two variables inequalities and the picture below are self-explanatory. The pictures depict how various conditions of inequalities are represented graphically. Try to understand why different area are shaded to depict two equations in question.

The student who asked me the question about how to draw graph inequalities in Excel had an equation similar to -5X+6Y>12 as shown in the picture above.

I have already discussed how to plot simple linear equations on Microsoft Excel but today I am going to explain how to plot inequalities in Excel. I will start with a simple equation and then extend it to equations dealing with inequalities on Excel. An additional thing that need to be done in depicting inequalities is to draw the shaded area below or above the graph depending upon whether the inequality is “<=” or “>=”.

In short:

<=: Graph is depicted with dotted line and shaded area is below the graph.

>=: Graph is depicted with a continuous line and the shaded area is above the graph.

Watch the video below to learn how to plot this graph: