This lesson provides students with the description of an authentic situation (buying DVDs) and data points that fit that situation. Students graph the line that contains those points; determine its y-intercept, slope, and equation; and interpret the slope and y-intercept in the context of the problem. Finally, students extrapolate to determine a functional value that is outside the domain they have graphed. Questions for students, suggestions for assessment, extensions of the lesson, and questions for teacher reflection are included. (author/sw)

In this lesson, students apply their knowledge of linear equations and graphs in a cost comparison between two DVD rental plans. Students plot data points corresponding to the cost of multiple DVD rentals on one plan. They connect the points to form a line and discuss the graph. The students observe that the slope, rate of change, is constant, develop an equation for the line, determine a y-value for a point outside the domain graphed, and discuss its significance. The specific career fields that where this resource will be applicable are Finance, Marketing, or any other career field that deals with business applications. (jrs)