Read the following quick sheet: Linear Algebra Explained in 4 Pages

You should be familiar with the following concepts:

• adding vectors
• matrix multiplication
• matrix inverse
• how to visualize lines and planes and hyperplanes; dot product
• systems of linear equations
• eigenvalues

An excellent visual introduction to Linear Algebra can be found here.

It is highly recommended that you watch the above video series.

For those looking for a more in-depth treatment of linear algebra, you should check out MIT's 18.06 Linear Algebra Course