We have discussed general methods for solving arbitrary equations, and looked at the special class of polynomial equations. A subclass of the latter comprises all the systems of linear equations to which the area of linear algebra is devoted. In fact, many a problem in numerical analysis can be reduced to one of solving a system of linear equations. We already witnessed this in the use of Newton’s method to solve a system of nonlinear equations. Other applications include solution of ordinary or partial differential equations (ODEs or PDEs), the eigenvalue problems of mathematical analysis, least-squares fitting of data, and polynomial approximation.