1. Goal Find an equation of a line that fits a set of points. Big Idea When points lie nearly on a line, it is useful to determine an equation for a line that lies on or comes close to the points.

2. Warm-Up Graph the three points (1, 5), (2, 9), and (4, 12). 1.Eyeball two points on a line that is close to these points and find its equation. 2 4 6 14 12 10 8 6 4 2

3. The table below shows the number of U.S. cell phone subscribers in millions from 2000 to 2006. Yr Yr since Subscribers 2000 (millions) 2000 0 97.0 2001 1 118.4 2002 2 134.6 2003 3 148.1 2004 4 169.5 2005 5 194.5 2006 6 219.4 d. Use the equation of the line to predict the number of cell phone subscribers in 1996. The actual number was 38.2 million. Did the line of best fit over or under predict the number of 1996 subscribers? e. Use the equation to predict the number of subscribers in 2010. Do you expect the equation to over predict or under predict the number of 2010 subscribers? Explain why. a.Using a graphing calculator, create a scatterplot of the points (Yr since 2000, Total Subscribers). b. Use a calculator to find an equation for the line of best fit. Graph the line in the same window as the scatterplot. c. In this situation what is the meaning of x = –4 and x = 10?

4. 2 4 6 220 200 180 160 140 120 100 I could not find points on the grid lines, so I picked points ≈½ way. a.