The aim of this research is to analyse the tasks proposed in the teaching of systems of two linear equations with two unknowns, in the 8th grade mathematics textbook, in the light of Duval's theory of semiotic representation registers (2003). This is a qualitative, documentary study. From the analysis we carried out, we realised that the proposed tasks present a variety of registers such as algebraic, natural language and graphical. Tasks that refer to treatments - 64 per cent - are also favoured over conversions - 36 per cent - where there is only coordination in one direction. In this way, we can see that the students solve everything in a mechanical and memorised way, because the proposed tasks suggest it. In our opinion, this may be one of the factors contributing to the student's poor learning performance in maths. According to the theory studied, we can conclude that the tasks proposed in the textbooks should make it easier for the student to co-ordinate the registers; these co-ordinations should occur in both directions. However, we suggest that more tasks should be proposed that refer to conversions in relation to treatments or that there is a balance.