Title: Point Slope Form Standard Form
1Point Slope FormStandard Form
Writing Equations of Lines
2Point Slope Form
Variable
Variable
y y1 m(x x1)
Slope
(x1, y1)
3Steps
- Write the equation
- Determine the slope
- Substitute slope for m
- Substitute values from a point for x1 and y1
- Eliminate any double signs (i.e. -, --, etc.)
4Why does the point-slope form work?
Find the slope between (x1, y1) and (x, y).
Reflexive property
Point-Slope Form
5Write the equation of the line with slope 3 and
passing through the point (1, 5).
Use Point-Slope Form
y y1 m(x x1)
6Write the equation of the line with slope ¾ and
passing through the point (-5, 3).
Use Point-Slope Form
y y1 m(x x1)
7Write the equation of the line with slope -2/3
and passing through the point (2, -4).
y y1 m(x x1)
8Write the equation of the line passing through
the points (-2, 6) and (3, -1).
Find the slope
y y1 m(x x1)
let's use (3, -1)
9Write the equation of the line passing through
the points (4, 3) and (6, 8).
Find the slope
y y1 m(x x1)
let's use (4, 3)
10Write the equation of the line passing through
the points (4, -3) and (-7, -1).
Find the slope
y y1 m(x x1)
let's use (4, -3)
11Standard Form
Constant
Both Cant Be 0
Integer When Possible
Any Constant
12Steps
- Basically, solve for C
- Get the x and y on one side of the
- Get the constant on the other side of the
13Convert y 3x 2 to standard form.
multiply both sides by -1
14Convert y 6776x to standard form.
multiply both sides by -4
15Convert y 6776x to standard form.
multiply both sides by 7
16Convert y 6776x to standard form.
multiply both sides by -2
17Convert y 6776x to standard form.
multiply both sides by 15
18More on Slope
- Parallel lines have the same slope
- Perpendicular lines have opposite reciprocal
slopes
Parallel Lines
Perpendicular Lines
19Write the equation of the line parallel the line
4x 5y 7 that passes through the point (-3, 7)
What is the slope of the given line?
y y1 m(x x1)
20Write the equation of the line perpendicular the
line 3x 2y 9 that passes through the point
(2, 5)
What is the slope of the given line?
y y1 m(x x1)