 In this video, we provide the solution to question number one for practice exam number one for math 1050. We are given three graphs and asked to identify which of these graphs are in fact functions. If you're given the graph here, it'll be a function if it passes the vertical line test. That is every vertical line that intersects the graph should do so only at one point. So when we look for example at graph one right there, that's going to pass the vertical line test. There is a vertical asymptote right here. That's not a problem. There's no intersection of that vertical line. So one is going to be a function. When we look at graph two, same thing right here, all these vertical lines intersect the graph only at one point. So it passes the vertical line test. Two is a function. You'll notice with three over here, you're not getting hit by the vertical line. That's okay. No problem there. The issue is on the right hand side of this picture, you'll notice that there do exist vertical lines. Many of them actually that intersect the graph at multiple occasions. So this one is not a function. So if I identify that graph one and two are in fact functions, so we would select choice D.