Elementary Linear Algebra: Applications Version, 11th Edition (http://bcs.wiley.com/he-bcs/Books?action=index&itemId=1118434412&bcsId=8466)

Solving linear systems with matrix equations (https://www.khanacademy.org/math/precalculus/precalc-matrices/solving-equations-with-inverse-matrices/v/solving-matrix-equation)

Solutions to systems of equations: consistent vs. inconsistent (https://www.khanacademy.org/math/algebra/systems-of-linear-equations/possible-number-of-solutions-of-systems-of-linear-equations/v/consistent-and-inconsistent-systems)