Point-Slope Form (given a point and slope)
04/19/23
Heading
TSWBAT: write an equation given a point and the slope using the Point-Slope formula.
Students verify that a point lies on a line, given an equation of the line. Students are able to derive linear equations by using the point-slope formula.
5.6A
Notes
14, 1 ,
2m
Ex.
Graph the line with the given slope that contains the given point. Find the y-intercept and then write the equation of the line.
1
2m
3b
y mx b
y x
1
23
13
2y x
Notes
2, 2 , 3m Ex.
Graph the line with the given slope that contains the given point. Find the y-intercept and then write the equation of the line.
3m4b
y mx b y x 3 4
3 4y x
Now you try.
• Point-Slope Form
Notes
1 1y y m x x
Before we were given the graph, and told to find the equation.
1 1,
m
x y
slope
point
Now we will be given a point and the slope, and told to find the equation.
It’s called the Point-Slope Formula
because you need a point and the slope to write the equation of
the line.
NotesWrite the equation of the line.
2, 7 , 3mEx.
1 1y y m x x
y x 7 3
3 1y x
Write this every time.
Plug in the values.
Label your points.1x 1y
2
7 3 2y x 7 3 6y x 7 7
Distribute.
Get y by itself.
Now you try.
4, 3 , 2mEx.
1 1y y m x x
y x 3 2
2 5y x
1x 1y
4
3 2 4y x 3 2 8y x 3 3
NotesWrite the equation of the line.
1, 8 , 4m Ex.
1 1y y m x x
y x 8 4
4 12y x
Write this every time.
Plug in the values.
Label your points.1x 1y
1
8 4 1y x 8 4 4y x 8 8
Distribute.
Get y by itself.
Now you try.
2, 4 , 3m Ex.
1 1y y m x x
y x 4 3
3 10y x
1x 1y
2
4 3 2y x 4 3 6y x 4 4
NotesWrite the equation of the line.
4, 3 , 2m Ex.
1 1y y m x x
y x 3 2
2 5y x
Write this every time.
Plug in the values.
Label your points.1x 1y
4
3 2 4y x 3 2 8y x 3 3
Distribute.
Get y by itself.
Now you try.
4, 7 , 1m Ex.
1 1y y m x x
y x 7 1
11y x
1x 1y
4
7 1 4y x 7 1 4y x 7 7
NotesWrite the equation of the line.
16, 7 ,
3m
Ex.
1 1y y m x x
y x 71
3
19
3y x
Write this every time.
Plug in the values.
Label your points.1x 1y
6
17 6
3y x
17 2
3y x
7 7
Distribute.
Get y by itself.
Now you try.
54, 3 ,
2m
Ex.
1 1y y m x x
y x 35
2
513
2y x
1x 1y
4
53 4
2y x
53 10
2y x
3 3
1 1
NotesWrite the equation of the line.
18, 6 ,
4m
Ex.
1 1y y m x x
y x 61
4
14
4y x
Write this every time.
Plug in the values.
Label your points.1x 1y
8
16 8
4y x
16 2
4y x
6 6
Distribute.
Get y by itself.
Now you try.
1
46, 1 ,
3m
Ex.
1 1y y m x x
y x 1 4
3
49
3y x
1x 1y
6
41 6
3y x
41 8
3y x
1 1
1
Summary
To find the equation of a line given a _____ and the slope use the point-_____ formula. Plug in the values into the ________. Next simplify the expression and get y by _____ on the left side. Sometimes you need to do leave, _______, change.
pointslope
formulaitselfchange
Today’s Homework
1. Pencil ONLY.2. Must show all of your work.
• NO WORK = NO CREDIT3. Must attempt EVERY problem.4. Always check your answers.
Rules for Homework
Homework 5.6A
1. 1, 6 , 2mWrite the equation of the line.
2. 2, 1 , 3m 3. 3, 3 , 2m
4. 3, 9 , 4m 5. 2, 7 , 3m 6. 5, 2 , 1m
17. 3, 1 ,
3m 3
8. 4, 10 ,2
m
410. 6, 6 ,
3m 1
9. 8, 5 ,4
m
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