http://www.greenemath.com/
Here, we will learn how to work with matrices in algebra. We will cover all of the basic operations, such as adding and subtracting matrices, multiplying matrices, Gauss-Jordan and Gaussian Elimination methods, finding determinants, finding the inverse, and Cramer's rule.
0:00 Introduction to Matrices
15:58 Adding and Subtracting Matrices
36:54 Multiplying a Matrix by a Scalar
54:45 Multiplying Matrices
1:21:08 Gauss-Jordan Elimination with Two Variables
1:56:26 Gauss-Jordan Elimination with Three Variables
2:35:52 Gauss-Jordan Elimination with Four Variables
2:53:21 Finding the Determinant of an n x n Matrix
3:23:00 Finding the Determinant of a 4 x 4 Matrix
3:38:22 Finding the Area of a Triangle Using Determinants
3:50:29 Testing for Collinear Points Using Determinants
3:57:56 Finding the Equation of a Line Using Determinants
4:13:55 How to Find the Inverse of a Matrix
5:02:21 Solving Linear Systems Using Inverse Matrices
5:40:08 How to Find the Transpose of a Matrix
5:44:16 How to Find the Adjoint of a Matrix
6:07:24 How to Find the Inverse Using the Adjoint
6:35:39 Cramer's Rule 2 x 2
7:01:46 Cramer's Rule 3 x 3