Results in Mathematics Education, from different theoretical perspectives, highlight students' difficulties with graphs, both in interpreting given ones and in producing their own graphs. In this paper, we take an affective lens to understand both a student's relationship with mathematical graphs and a teacher's role when a task with a graph is assigned. The episode under analysis has many sources of interest for us, since it allows us to reflect on various features of blended learning formats; it involves the use of formulas and graphs; and the teacher-students' relationship unfolds as a relation among varying motivational states.