1.1 Integers and Rational Numbers

8.4. Graphing Using Intercepts www.ck12.org8.4 Graphing Using InterceptsIntroductionSanjits office is 25 miles from home, and in traffic he expects the trip home to take him an hour if he starts at 5 PM.Today he hopes to stop at the post office along the way. If the post office is 6 miles from his office, when will Sanjitget there?If you know just one of the points on a line, youll find that isnt enough information to plot the line on a graph. Asyou can see in the graph above, there are many linesin fact, infinitely many linesthat pass through a single point. Butwhat if you know two points that are both on the line? Then theres only one way to graph that line; all you need todo is plot the two points and use a ruler to draw the line that passes through both of them.There are a lot of options for choosing which two points on the line you use to plot it. In this lesson, well focus on twopoints that are rather convenient for graphing: the points where our line crosses the x−and y−axes, or intercepts.Well see how to find intercepts algebraically and use them to quickly plot graphs.154