La ecuación lineal con dos variables : entre la unicidad y el infinito

Abstract

In this work we show the results of a study we have done on 6 students dealing with two variable linear equations, when they have previously elaborated a conception -in the context of one variable linear equation- according to which equations are numerical equalities and letters are numbers to be discovered. The elements on which 5 out of the 6 students ground to uphold unicity of solutions, and those used by the one who can conceive several solutions from the very beginning, are described. We then report our interpretation of the students’ work throughout the interview in terms of the notions of variable, infinity of solutions, and also dependence and covariation.