Another way to model systems of equations is to use an interactive website. The following website uses Algebra Tile shapes with triangles for y-values. Let's try the first set of systems of equations on the website:

On the website, a rectangle represents x, a triangle represents y, and squares represent units. Red is negative and blue is positive.

Look at the screen shot below to see how the webpage is set up and the directions to follow.

Source: Algebra Tiles, 26 Design

Your goal is to eliminate the rectangle, x, or the triangle, y. The same amount of red and blue in the same shape will remove them. That process on the website is called Zero Out.

Notice that the y value is +1 and -1. So you will use addition to eliminate the y-values. The y-values will cancel each other out if you add them together. You need to move the bottom equation up to be added to the first like this.

Source: Algebra Tiles, 26 Design

When you click Zero Out, the y tiles are eliminated.

Source: Algebra Tiles, 26 Design

Then you can see that by dividing both sides of the line by 4, x = 3.

Now try to work this problem yourself at the website.

Algebra Tiles