2. They are boring! They have no use in life. STEREOTYPES ABOUT PARALLEL AND PERPENDICULAR LINES

7. PARALLEL AND PERPENDICULAR LINES ARE EVERYWHERE

8. y = mx + b m is the slope of the line b is the y-intercept REVIEW: SLOPE INTERCEPT FORM Life is easy when you’re in slope intercept form

9. y = mx + b The y-intercept is the y value when x = 0. Visually, the y-intercept is y value when the line crosses the y axis http://www.mathsisfun.com/data/function- grapher.php Y -INTERCEPT

10. m y = mx + b Slope Slider Slope of vertical lines? SLOPE

11. 3y = 6x + 9 5y = 10x y = -1 x = 3 IDENTIFYING THE SLOPE AND THE Y-INTERCEPT

12. y = mx + b Given the slope, m, and a point, (x, y), then we can find b, the y-intercept. b = y – mx Once we find b, we can find the equation of the line. REVIEW: FINDING THE EQUATION OF THE LINE GIVEN A SLOPE AND A POINT ON THE LINE

13. p = (-2, 2) m = 4 p = (-3, 4) m = -2 p = (-2, 2/3) m = -4/3 PRACTICE: FINDING THE EQUATION OF THE LINE GIVEN THE SLOPE AND A POINT ON THE LINE

14. 1. Graph line segments. Be sure that each endpoint is an integer coordinate, such as (1,3) or (-3,0) Compute and record their slope. 2. Then graph a parallel line to each of the three line segments. Compute and record the slopes of the parallel lines. Then delete the parallel lines. 3. Then graph a perpendicular line to each of the three line segments. Compute and record the slopes of the perpendicular lines. GRAPHING ACTIVITY

18. PARALLEL LINES Two lines are parallel The lines never intersec t Slopes are equal

19. y = (1/3)x + 2 y – 1 = 6x 2y = 5x + 3 4y = 8x y = 6 x = -3 FIND THE SLOPE OF A PARALLEL LINE

20. PERPENDICULAR LINES Two lines are perpendicular The lines intersect at right angle Slopes are negative reciprocals

21. y = -3x – 2 y = (1/3)x + 2 y – 1 = 6x 2y = 5x + 3 y = 6 x = -3 FIND THE SLOPE OF A PERPENDICULAR LINE

22. y = (1/3)x + 2, p = (2, -3) 2y = 5x + 3, p = (1/2, 2/3) y = 6, p = (6, 0) x = -3, p = (1, 2) FIND THE EQUATION OF THE PARALLEL LINE THAT PASSES THROUGH THE GIVEN POINT.

23. y = -3x – 2, p = (-1, 4) 4y = 8x, p = (1, 1/3) y = 6, p = (6, 0) x = -3, p = (1, 2) FIND THE EQUATION OF THE PERPENDICULAR LINE THAT PASSES THROUGH THE GIVEN POINT.