1. 5.7 Parallel and Perpendicular Lines
Parallel Lines -
2 lines that never intersect
They have the same slope
m1 = m2
They have different y-intercepts
b1 ≠ b2
Perpendicular Lines -
2 lines that intersect
They create 4 right angles
They have different slopes
(m1)(m2) = -1
They can have the same y-intercept

2. Identify the lines as parallel or perpendicular.
Ex A) 2x + 5y = x + 10y = 18
Line 1
Line 2
2x + 5y = 7
4x + 10y = 18
-2x
-2x
-4x
-4x
5y = -2x + 7
10y = -4x + 18 5 5 5 10 10 10
Parallel

3. Ex B) Line 1 Line 2 3x + 6y = 8 -3x -3x 6y = -3x + 8 6 6 6
(m1)(m2) = -1
Perpendicular

4. Write an equation in slope-intercept form that is parallel to the given line and
passes through the given point.
Ex C)
Point-Slope Form
Slope-Intercept Form

5. Write an equation in slope-intercept form that is parallel to the given line and
passes through the given point.
Ex D)

6. Point-Slope Form
Slope-Intercept Form

7. Ex E) m= opposite and reciprocal
Write an equation in slope-intercept form that is perpendicular to the given line
and passes through the given point.
Ex E)
m= opposite and reciprocal
Point-Slope Form
Slope-Intercept Form

8. Write an equation in slope-intercept form that is perpendicular to the given line
and passes through the given point.
Ex F)

9. Point-Slope Form
Slope-Intercept Form