This lecture covers the Gaussian elimination method, which is used to transform a given matrix into a reduced row-echelon form by applying elementary row operations. The method involves steps such as exchanging rows to obtain a pivot in the leading diagonal and adding multiples of one row to others to obtain zeros below the pivot. The lecture also explains how to determine if two matrices are row equivalent and how to convert a matrix into reduced row-echelon form. The process is illustrated with examples and proofs, emphasizing the importance of the Gaussian elimination algorithm.