If you're looking for a way for students to discover linear functions in an interactive way, this is the spreadsheet you're looking for. Students will be able to discover the slope, x and y intercepts, and so much more, As the slope and y-intercepts change, so does the graph. Microsoft Excel 2002 and above is required. Make sure you enable macros.
Linear Functions Exploration by Montario Fletcher is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.