The Geometry of Linear Equations -- Lecture #1. How to set up and solve matrix equations.
Gilbert Strang, 18.06 Linear Algebra, Spring 2005. (Massachusetts Institute of Technology: MIT OpenCourseWare), http://ocw.mit.edu (Accessed November 16, 2008). License: Creative Commons BY-NC-SA. More info at: http://ocw.mit.edu/terms