## Gauss-Jordan Elimination App

What it teaches:

This app teaches the Gauss-Jordan elimination method of solving a system of linear equations. Here is a screen shot:

Because the app allows only elementary row operations and because it does the arithmetic, you can stay focused on the method and not get bogged down by the details.

How it works:

• You start with either a new system of 2, 3, or 4 equations, or you can open a previously saved system of equations.

• Once all the coefficients are entered, you can either click on Automatic to go straight to the solution, or on Manual to solve the system yourself, step-by-step, by applying the three types of elementary row operations.

• In Manual mode you can click on Assist if you are stuck and the app will do the next step for you.

• As the screen shot shows, you first test a row operation.  The tentative result is shown in red below the row that will change. If this is what you intended then the operation is carried out.  (The idea is that you can see the system of equations both before and after the operation.)

Some ideas for teachers:

• You can start with a solution and reverse the Gauss-Jordan procedure; thus creating a question in which your students will encounter only integers when they solve it.

• By letting the right side of a system of equations be (1, 0, 0), then (0, 1, 0), then
(0, 0, 1), you can explain the idea behind the inverse matrix.

Where to now?

• Home to the MathOnWeb Software homepage.
• Back to see the other 9 apps in the Technology Suite.