1. 3.6 Finding the Equation of a Line

2. Slope-Intercept Form Slope y-intercept
What are the two things needed to write the equation of a line in slope-intercept form? 1. 2.
Slope
y-intercept

3. Write an Equation Given a Slope and a Point on the Line
Example:
Set up your equation by substituting in the slope.
What can you do to find the y-intercept?
Find the y-intercept!
What is the equation of the line?

4. Determine an equation in the form
of the line passing through the given point
P with the given slope m. 1. 2.

5. Write an Equation Given 2 Points on the Line:
Example:
Find the slope!
Set up your equation by substituting in the slope.
What can you do to find the y-intercept?
Find the y-intercept!
What is the equation of the line?

6. Determine an equation in the form of the line containing the two given points.3. 4.

7. Parallel Lines parallel same
In your graphing calculator, graph the following:
What do you notice about all three graphs?
What is the same about each equation?
What is different about each equation?
So, to sum it up lines have the slope!
parallel
same

8. 6. ; parallel to the line containing and
Determine the equation in the form of the line through the given point satisfying the given equation.
; parallel to
; parallel to the line containing
and

9. Perpendicular Lines opposite reciprocal
Perpendicular lines on the other hand have
slopes!
opposite
reciprocal

10. Find the slope of a line perpendicular to the given line.7. 8. 9.

11. 11. Perpendicular to the line through and
Determine the equation in the form of the line through the given point satisfying the given equation.
perpendicular to
Perpendicular to the line through
and