Parallel and perpendicular WarmUp 1 Write and graph

Parallel and perpendicular

Warm-Up 1. Write and graph the new equation when y = 2 x + 4 is shifted down 8 units. 2. What happens to the graph when the slope in y = 2 x + 4 is changed to ½ and the y intercept is changed to -1?

Opening Graph the following: 1. y = 3 x + 2 2. (0, 4) (1, 7) 3. m = 3, b = -2 What do you notice about the lines? What do they have in common? Lines with the same slope are parallel.

Opening What do you notice about the lines? What do they have in common? Lines with slopes that are negative reciprocals are perpendicular lines. We can prove the lines are perpendicular if the product of their slopes = -1.

Work Time (we will close with some of these) Find the equations for the following and determine if they parallel, perpendicular or neither. 1. y = 2 x – 2 3. (1, 5), (0, 7) 2. m = -2, b = 2 4. (5, 1), (7, 0)

**perpendicular lines form right angles •

• Parallel lines have the _______. • Perpendicular slopes are ______.

PARALLEL PERPENDICULAR DAY 2

Warm-Up • Describe in words the graph of y = 3 • Describe in words the graph of x = -2 • Describe in words the parent function

Opening Original slope 4 -1/8. 25 0 Parallel Slope Perpendicular Slope

Explore: Which lines are parallel? Which are perpendicular? • • • Line 1: x + 5 y = 2 Line 2: passes through (-6, 3) and (-2, 1) Line 3: passes through (-1, -6) and (0, -8) Line 4: -10 y – 2 x = 0 Line 5: see graph

Are these perpendicular? How can you be sure? ? ?

Define: What does Parallel mean? What does perpendicular mean?

Work Time Write the equation of the line that passes through (1, -2) and is parallel to the line f(x) = -4 x + 6

Work Time • Write the equation of the line that passes through (4, -5) and is perpendicular to the line y = 2 x + 3.

Explore • What is the equation of the line that is perpendicular to the line y = -(¼)x + 5 and passes through the point (-6, 4)?

Homework • Assignments are in netschool • Workbook or textbook lessons 4. 5 and 5. 5