 So a common student complaint is the exam was nothing like the homework, and a common instructor response, but it asked the same type of questions. And so to reconcile these two statements, here's a little insight on how instructors create exams from homework problems. So during the course of a unit, you might be asked questions like the following, write the equation of the line shown, solve this equation, let h of x be the altitude of a plane and interpret something in function notation, but on the exam you see this question. And it's nothing like these other questions that you've been asked, so how is this a reasonable exam question? And in fact this question is based on the questions you've answered, but there are three important changes. The ending point has moved, the starting point has moved, and the venue has changed. Let's talk about that. So this question should have some interpretation like the following. At one o'clock the altitude is zero kilometers above sea level. So that's the ending point of this question, but let's go a little bit further. Let's change that ending point and recognize that this also means that the plane is at sea level. And when we come to the exam question, since the exam question identifies that the plane took off from sea level, this suggests a time when the plane took off. Of course, we weren't actually given h of 1 equals zero, and that's because the starting point was also changed. Now we can find this by solving the equation, but we don't actually have that equation, but we can get it by answering this question, but we weren't given the graph. However the first thing we do to find the equation is to find two points on the graph, and we're given two points on the graph. And so let's put that all together. The given information tells us that h of x is a line through two points, and we can find the equation of the line. We then solve h of x equals zero, and that tells us the plane took off at one o'clock. And so let's talk about ways you can prepare for an exam. In any problem you can always ask if there's an earlier starting point. Instead of starting with an equation, you might need to find the equation, and maybe instead of being given a graph, you might need to produce the graph. Another possibility is to ask, what can I do with the answer? Once you've solved for a variable, what does it represent? Or once you've graphed an equation, what else can you find? And finally change the venue. In any problem, always ask how else could this information be presented? What information did the graph give you, and how else could it have been presented? Or what information did you get from the equation, and how else might it have been given to you?