1. It’s What’s Going On!

2. Recall y = mx + b is the equation of a line m is the value of the slope of a line (rise over run) b is the y-intercept m = 1 __ 2 b = 0

3. Parallel Lines: Lesson Parallel lines have the same slope or m value Parallel lines are always the same distance apart Parallel lines move in the same direction and never meet Same distance throughout

4. Parallel Lines: Application Graph the following lines: y=4x-3 and y=4x-1 What is the relationship between these lines? Graph two more lines with this relationship y = 4x-1y = 4x-3

5. Parallel Lines: Application Graph the line y=2x+1 Graph a line parallel to this line with a y- intercept at 4 y = 2x+1y-intercept

6. Perpendicular Lines: Lesson Perpendicular lines intersect each other at 90° angles Perpendicular lines have slopes that are negative reciprocals of each other.

7. Perpendicular Lines: Application Graph the following lines: y=1x+1 and y=-2x+1 What is the relationship between these lines? Graph 2 more lines with this relationship. _ 2 y = 1x + 1 y = -2x + 1 __ 2

8. Perpendicular Lines: Application Graph the line y=3x + 2 Graph a line perpendicular to this line with a y-intercept at 3. 4 _ y = 3x + 2 _ 4

9. Horizontal Lines Introduction Lines that are horizontal have a slope of zero. They have "run", but no "rise". The rise/run formula for slope always yields zero since

10. Horizontal Lines: Lesson Horizontal lines have no x-intercept They are parallel to the x- axis If (0,1) is y-intercept of a horizontal line, then the equation of the line is y=1 Have a undefined slope

11. Horizontal Lines: Example Remember, horizontal lines are parallel to the x-axis. Example 1: y=2 Example 2: y=4

12. Horizontal Lines: Application Graph the following lines: y=3 y=1 y=-2 y=-3 Click the mouse to show answers

13. Vertical Lines Introduction Lines that are vertical have no slope (it does not exist). They have "rise", but no "run". The rise/run formula for slope always has a zero denominator and is undefined.

14. Vertical Lines: Lesson Vertical lines have no y- intercept They are parallel to the y-axis If (1,0) is x-intercept of a vertical line, then the equation of the line is x=1 Have a undefined slope

15. Vertical Lines: Example Remember, vertical lines are parallel to the y-axis. Example 1: x=-2 Example 2: x=1

16. Vertical Lines: Application Graph the following lines: x=2 x=-3 x=4 x=1 Click the mouse to show answers

17. Horizontal & Vertical Reloaded Graph the following lines: x=2 y=3 You are now a master of Horizontal and Vertical lines

18. Web-sites to visit: http://www.math.com/school/subject3/lessons/S3 U1L3GL.html http://www.math.com/school/subject3/lessons/S3 U1L3GL.html http://www.sci.wsu.edu/~kentler/Fall97_101/nojs/ Chapter3/section2.html http://www.sci.wsu.edu/~kentler/Fall97_101/nojs/ Chapter3/section2.html http://regentsprep.org/Regents/math/line- eq/EqLines.htm http://regentsprep.org/Regents/math/line- eq/EqLines.htm http://www.hoxie.org/math/algebra/stline1.htm

19. Horizontal and Vertical Lines Parallel and Perpendicular Lines