Justino, Júliavan den Berg, Imme2014-03-192014-03-192011http://hdl.handle.net/10400.26/6122We study systems of linear equations with coefficients and second member having uncertainties of type o (.) or O(.); in fact, we do not use this functional form of neglecting but an alternative formulation within non-standard analysis using sets of infinitesimals. We call this kind of systems flexible systems of linear equations. In some cases an exact solution may not exist but we present a general theorem that guarantees the existence of a maximal solution. This maximal solution is produced by Cramer’s Rule; depending on the size of the uncertainties appearing in the matrix of coefficients and the second member some adaptations may be needed.engCramer’s RuleExternal numbersNonstandard analysisconference object