We are studying two groups of preservice teachers' conceptions, progression and especially the concept of function in connection to y=x+5 when they are taking a course in algebra or one in calculus in their third and sixth term, respectively, in a teacher preparation program. There is a similar development in that they use to a higher degree a numerical interpretation before the course, which decreases after the course with a growth in linear and functional interpretation with the existence of two variables as a large and rather stable category. The group in their sixth term have a slightly more elaborated language and way of looking at y=x+5 than the group in the third term. For a majority of preservice teachers, in both groups, the concept of function is not evoked in connection to y=x+5. (Contains 6 footnotes, 1 figure and 2 tables.) [For complete proceedings, see ED500858.]