For a given set of m linear equations in n unknowns x1, x2,…xn,
the augmented matrix is the matrix
obtained by adjoining to the matrix of coefficients an extra column of entries taken from the right-hand sides of the equations. The solutions of a set of linear equations may be investigated by transforming the augmented matrix to echelon form or reduced echelon form by elementary row operations. See Gaussian elimination, Gauss-Jordan elimination.