Video of the lecture.
Handwritten notes of the lecture.
Waiting room video: Numberphile on Fermat's Last Theorem.

Then recalled how to multiply two matrices, and recalled what is meant by the inverse of a matrix.

Explained how the inverse of an n×n matrix can be useful for solving a system of n linear equations (=no powers or products of unknown variable) in n unknowns.

Ended with an explanation of how to use row operations to find the inverse of an n×n matrix.