A system of linear equations consists of equations of the form a_{11}x_{1}+a_{12}x_{2}+a_{13}x_{3}+...=b_{1}, a_{21}x_{1}+a_{22}x_{2}+a_{23}x_{3}+...=b_{2}, .... Such a system contains several unknowns. It is solvable for n unknowns and n linear independant equations. The coefficients of the equations are written down as an n-dimensional matrix, the results as an one-dimensional matrix. The augmented matrix, which is used here, separates the two with a line.