O.k. This is definitely the lesson with the longest name. We used to call these literal equations back in the day, but now they are just linear equations with unspecified constants. Of course, what tend to show up on the New York State Regents exams could be linear, could be quadratic, you just never know. Still, this is a good lesson to stress the importance of reversing the actions done to the input variable in order to find its value.