1. 4.7 Parallel and Perpendicular Lines
Parallel lines have the same slope.
All vertical lines are parallel.
All horizontal lines are parallel.
Perpendicular lines have opposite reciprocal slopes.
If m = 3, then the m = -1/3
If m = -2/3, then the m = 3/2

2. Write an equation of the line that is parallel to the graph of 2x + y = 5 and passes through the point (3,1).
Since the slope is -2.
Using the point (3,1) and the parallel slope of -2, plug all into the point-slope form
Distribute
Add 1 to both sides

3. Use point-slope form with slope = -6 and point given (2,4)
Write an equation of the line that is perpendicular to the graph of x - 6y = 2 and passes through the point (2,4).
Use point-slope form with slope = -6 and point given (2,4)

4. Try These Two to Practice!
Write the slope-intercept form of an equation for the line that passes through (4,-2) and is parallel to the graph of
Write the slope-intercept for of an equation for the line that passes through (4,-1) and is perpendicular to the graph of

5. Page 239 #1-7 odd
1. y = -2x -1
3. y = 2x – 5
5. Find the slope of segment AC
6/7
Find the slope of segment BD
-7/6
They are opposite reciprocal slopes therefore they are perpendicular. 7.
Homework #32: p , 36, 37