In Problem 1, students are given data from music sales in a Lists & Spreadsheet page. They use this scenario to find the solution to a system of linear equations.
They use the cells to calculate the slope. Students use the expression = b2 – b1 in cell B3. They may see that since there is only a difference of 1 year, the difference between the sales data for CDs, digital albums, and individual songs is equal to the slope of the line.