Keynote and solving systems of equations.

This past summer I learned how to create animation using keynote.  I just realized today that I could use keynote to prepare an animated presentation showing the steps to solve systems of equations either by graphing, substitution or elimination.  I show videos, demonstrate the process for substitution and elimination but I think I need something a bit more because it is not quite enough to help them learn it as well as they should.  Since I've done a keynote animation showing classification of triangles by sides and by angles, I know the basics.  But tonight, I realized that I could apply the same animation process to create something where coefficients and variables might move around. So I have a process for next weekend - create a keynote animation for solving systems of equations.