First let

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First lets review 5.1
Write the equation in slope-intercept form, given
m 3 ang b (0,-2)
Example m 3, b (0,-2)
y mx b
y __ x ___
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Write the equation of the line in slope-intercept
form.
m 3/2
b (0,1)
y mx b
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Given this equation, what is the slope and
y-intercept?
2x 2x
3y 2x 15
3 3 3
m 2/3
b (0,5)
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Review 5.2 Point-Slope Form
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Write the equation of the line in point-slope
form.
m -1/3
(0,3)
Or you can use any point
(3,2)
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Given (2,3) and slope -2, write the equation in
SLOPE-INTERCEPT
This is the equation of the line in point-slope
form!!
Now leave your answer in slope- intercept form.
3 3
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Given (-8,4) and slope -3/2, write the equation
in SLOPE-INTERCEPT
This is the equation of the line in point-slope
form!!
Now leave your answer in slope- intercept form.
4 4
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5.3 Writing equations of a line given two points
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Forms of a linear equation
Slope-intercept Form y mx b Point-Slope
Form y y1 m(x x1)
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If given two points,
(x1 , y1) and (x2 , y2)
First, find the slope using the slope formula.
Example contains (5, 8) and (2, 7)
m 15 3
m 5
m 7 -8 2 5
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If given two points,
Then use the slope and EITHER point to work like
the previous example.
y y1 m(x x1) y 7 5(x 2) y 7
5x 10
m 5, contains (5, 8) and (2, 7)
y 5x 17
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Writing an Equation Given Two Points
1. Calculate the slope of the line.
2. Select the form of the equation.
a. Slope-intercept form
b. Point-slope form
3. Substitute and/or solve for the selected form.
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Writing an Equation Given Two Points
Given the two ordered pairs, write the equation
of the line in point-slope form.
Calculate the slope.
or
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Writing an Equation Given Two Points in
point-slope form
Point-slope form
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Same example Writing an Equation Given Two
Points in slope-intercept form.
Start by using point-slope form
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2.) Writing an Equation Given Two Points in
slope-intercept form.
(-5,7) (2,-7)
Start by using point-slope form
7 7
- 7 - 7
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EVERY ONE GET A COMMUNICATOR WITH A BLANK SIDE!!
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3.) Writing an Equation Given Two Points in
slope-intercept form.
(2,0) (-2,6)
Start by using point-slope form
3 3
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4.) Writing an Equation Given Two Points in
slope-intercept form.
(10,-5) (8,4)
Start by using point-slope form
- 5 - 5
- 7 - 7
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5.) Writing an Equation Given Two Points in
slope-intercept form.
(6,5) (-3,5)
Start by using point-slope form
5 5
5 5
Horizontal line
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6.) Writing an Equation Given Two Points in
slope-intercept form.
(-2,-4) (-4,8)
Start by using point-slope form
7 7
- 7 - 7
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7.) Writing an Equation Given Two Points in
slope-intercept form.
(-6,6) (9,1)
Start by using point-slope form
7 7
- 7 - 7
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NOW WHAT IF I GAVE YOU A GRAPH, TELL ME THE
EQUATION OF THE LINE
WHATS THE MAJOR DIFFERENCE BETWEEN THESE TWO
GRAPHS
So creating an equation using slope-intercept
form would NOT work!!!
The one on the right does not have a CLEAN
y-intercept!!
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Create the equation of the line using two points
on the line
(-3,4) (5,8)