Inverse functions....one part that I struggle to explain with this topic is why you only switch the variables when writing the equations for a function/relation, but not in a word problem. For example look at this site, http://www.classzone.com/eservices/home/pdf/student/LA207DBD.pdf If you go to that site....in example 1 for finding the inverse, you switch x and y. I get this---the domain and range switch so you flip the x and the y. How do you explain to kids that you do not switch the variables for word problems. For example, #3 on that link. For finding the inverse model, they simply solve the equation for w...they do not switch l and w. I mean, I get the idea intuitively, but I struggle trying to explain it. I see the little box suggests that it would be confusing since the variables represent real-life quantities, but I suspect students would wonder why to switch variables sometimes then. Any suggestions?