The document discusses the LU factorization method for solving systems of linear equations. It provides an example of applying the Gauss elimination method to a system of 4 equations with 4 unknowns. This results in an upper triangular system that can be easily solved with back substitution. The multipliers used in the row operations are stored in the lower triangular matrix L, while the upper triangular matrix U contains the coefficients from Gauss elimination. The product of L and U yields the original coefficient matrix A, representing the LU factorization of A.