This application of Editorial Editex S.A. solve systems of linear equations of 2 unknowns by substitution, equalization and reduction methods. It includes the following sections:  - Theory: contains a document in PDF format with a summary of contents.  - Practice: allows the resolution of systems and provides a graph of the functions associated with the entered equations, as well as a geometric interpretation of them.  - Test: allows you to perform a self-assessment with 10 test-type exercises c