Presentation Transcript
Lesson 4: Write Equations of Parallel and Perpendicular Lines :Lesson 4: Write Equations of Parallel and Perpendicular Lines
Slide 2:Parallel Lines
- If two nonvertical lines in the same plane have the same slope, then they are parallel.
- If two nonvertical lines in the same plane are parallel, then they have the same slope.
Slide 3:EX Write an equation of the line that passes through the point (-3, -5) and is parallel to the line y = 3x - 1. y = mx + b (-3, -5)
( x, y) +9 +9 m = 3 b = 4
y = mx + b y = 3x + 4
Slide 4:Perpendicular Lines
- If two nonvertical lines in the same plane have slopes that are negative reciprocals, then they are perpendicular.
- If two nonvertical lines in the same plane are perpendicular, then they have slopes that are negative reciprocals.
Slide 5:EX Write an equation of the line that passes through the point (4, -5) and is perpendicular to the line y = 2x + 3. y = mx + b (4, -5)
( x, y) +2 +2 y = mx + b b = -3