1. Daily Homework Quiz Graph each line. - x 3 2 y = 3– 1. y = 2x2x + 6 2. ANSWER

2. Daily Homework Quiz

3. 2.4 Part 2 Sept 14, 2012

4. Graph the lines y = -4x -3 and y = -4x +2 What do these 2 equations have in common? They are parallel ( ll ) What do you notice about the lines? Their slopes (m) are the same.

5. In a coordinate plane, 2 lines are parallel if and only if they have the same slope. Slopes of Parallel Lines

6. Testing if Lines are Parallel Are the lines y = ½x – 5 and y = -½ x +2 parallel? Since the slopes are different the lines are not parallel. Since the equations are both in standard form, rewrite both of them in y = mx + b form to find their slope and compare. Are the lines 6x – 3y = 5 and 4x + 2y = 4 parallel?

7. Find the opposite reciprocal of

8. What do these 2 equations have in common? They are perpendicular (  ) What do you notice about the lines? Their slopes (m) are the opposite reciprocal

9. In a coordinate plane, 2 lines are perpendicular if and only if their slopes are opposite reciprocal of each other (or their product is –1) Slopes of Perpendicular Lines

10. Testing if Lines Are Perpendicular Since the slopes are negative reciprocals of each other the lines are perpendicular.

11. Extra Practice Tell whether the lines are parallel, perpendicular, or neither. Parallel Perpendicular Neither Perpendicular

12. Graphing x = # Ex. Graph x = -3 The x coordinate is -3 no matter what the value of y is. xy -30 1 2 3 Choose any value of y So, the graph of x = # is always a VERTICAL LINE

13. Ex. Graph x = 4 The graph of x = 4 is VERTICAL LINE at 4.

14. Graphing y = # Ex. Graph y = 2 The y coordinate is 2 no matter what the value of x is. xy 02 12 22 32 Choose any value of x So, the graph of y = # is always a HORIZONTAL LINE

15. Ex. Graph y = -4 The graph of y = -4 is HORIZONTAL LINE at -4.

16. Homework 2.4 p.91 #32-43, 50-55