2. Equations of Lines (according to this textbook) 1.General FormAx + By + C = 0 2.Standard Form Ax + By = C 3.Slope-Intercept Form y = mx + b where A, B, and C are all integers and A is positive!

3. The Slope of a Line Ratio of change in y to the change in x. Always non-vertical

4. Example Please find the slope of the line passing through (-2,4) and (5,7) x1x1 y2y2 x2x2 y1y1

5. Try this one on your own and click when you have the answer. Please find the slope of the line that passes through (5,4) and (8,6). You should have gotten. If you did not get this answer, you can check out http://www.teachertube.com/view_video.php?viewk ey=7f50bdbda82f92aff1b9 http://www.teachertube.com/view_video.php?viewk ey=7f50bdbda82f92aff1b9 for an explanation.

6. Find the slope through each pair of points – click to check (3,-7) and (-4,2) (2,-9) and (-6,-9) (5,4) and (5,-8) undefined (no slope)

7. Slope-Intercept Form of a Line The slope-intercept form of a line is: y = mx + b

8. Slope-Intercept Form of a Line Find the slope-intercept form of the equation of the line with slope 3 that has y-intercept -2. The answer that you should have gotten is: y = 3x -2 If you did not get this answer, you can check out http://www.teachertube.com/view_video.php?vie wkey=3c5016881652983fb615 http://www.teachertube.com/view_video.php?vie wkey=3c5016881652983fb615 for an explanation.

9. The Point-Slope Form of the Equation of a Line The point-slope form of the equation of the line is:

10. Point-Slope Form of a Line Find the slope-intercept form of the equation of the line with slope -2 that passes through the point (4,-3) The answer that you should have gotten is: y = -2x + 5 If you did not get this answer, you can check out http://www.teachertube.com/view_video.php?viewke y=5c7bee808852f9020c0c http://www.teachertube.com/view_video.php?viewke y=5c7bee808852f9020c0c for an explanation.

11. Point-Slope Find the slope-intercept form of the equation of the line with slope 4 that passes through the point (-6,2) y = 4x +26

12. Point-Slope Find the slope-intercept form of the equation of the line that passes through the points (-3,5) and (1,3). The answer that you should have gotten is: If you did not get this answer, you can check out http://www.teachertube.com/view_video.php?viewkey=7 597d8ba9718c4d7d664 http://www.teachertube.com/view_video.php?viewkey=7 597d8ba9718c4d7d664 for an explanation.

13. A company purchases a $20,000 machine. In 4 years, the machine will be worth $10,000. Write a linear equation that related the value V of the machine after t years. V = -2,500t + 20,000

14. Parallel and Perpendicular Lines Two distinct nonvertical lines are parallel if and only if their slopes are equal. Two nonvertical lines are perpendicular if and only if their slopes are negative reciprocals of each other.

15. Try this one! Find the slope-intercept form of the equation of the line that passes through the point (5,-7) and is parallel to The answer that you should have gotten is: If you did not get this answer, you can check out http://www.teachertube.com/view_video.php?viewkey=64c34 7f7f21ae19b9765 http://www.teachertube.com/view_video.php?viewkey=64c34 7f7f21ae19b9765 for an explanation.

16. Find the general form of the equation of the line that passes through the point (1,-3) and is (a) parallel to 2x - 3y = 1 2x – 3y – 11 = 0 and (b) perpendicular to the line given by 2x - 3y = 1 3x + 2y + 3 = 0

17. Writing About Math Please pack your bags and then complete the following, to be handed in before you leave: Page 32

18. In 1990, a college had an enrollment of 5500 students. By 2000, the enrollment had increased to 7000 students. a.What was the average annual change in enrollment from 1990 to 2000? b.Use the average change in enrollment to estimate the enrollments in 1993, 1997, and 1999. c.Write the equation of the line that represents the data in part (b). What is its slope? Interpret the slope in the context of the problem. d.Write a short paragraph discussing the concepts of slope and average rate of change.