1. Ch6.1_6.2_SlopeParallelPerpendicularLines.notebook December 05, 2011
What is the slope?

2. Ch6.1_6.2_SlopeParallelPerpendicularLines.notebook December 05, 2011
Chapter 6.1 and 6.2
Slope­Intercept Form
Parallel & Perpendicular Lines

3. Ch6.1_6.2_SlopeParallelPerpendicularLines.notebook December 05, 2011
SLOPE
The "steepness" of a graph
Positive slope:
Negative slope:
2 points are needed to find the slope of a line
(x1, y1) (x2, y2)
+ up
y ­ y rise ­ down
slope = x2 ­ x1
2 1 run + right
­ left
Find the slope
Find the slope
y2 ­ y1
(1, 3) (4, 0) x2 ­ x1
Find the slope
y ­ y
(­2, 1) (3, 1) x2 ­ x1
2 1
Find the slope
y2 ­ y1
x2 ­ x1

4. Ch6.1_6.2_SlopeParallelPerpendicularLines.notebook December 05, 2011
Slope­Intercept Form
y = mx + b
m = slope b = y­intercept
5) y = x 6) y = 2

5. Ch6.1_6.2_SlopeParallelPerpendicularLines.notebook December 05, 2011
Parallel and Perpendicular Lines
Parallel: slopes are equal
m = 2 never intersect
m = 2
Perpendicular: slopes are negative
reciprocals
m = ­3 intersect at 900
m = 1
3
Example:
y = ­4x + 3
Slope of parallel line:
Slope of perpendicular line:
Example: Line through the points
(2,1) and (6, 7)
Slope of parallel line:
Slope of perpendicular line:
Are the following lines
Example: parallel, perpendicular, or neither?
6x + 2y = ­18
3y ­ 12 = 9x

6. Ch6.1_6.2_SlopeParallelPerpendicularLines.notebook December 05, 2011
Homework:
Worksheet 6.1 and 6.2