| Algebra 1 Notes
Chapter Seven
Section 7.1
Section 7.2
Section 7.3
Section 7.4
Section 7.5
Section 7.6
Section 7.7
Section 7.8
Section 7.9
Section 7.10
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Section
7.6 Finding an Equation of a Line
(Examples provided by Prentice
Hall)
Part I: The Slope-Intercept Equation
Write the equation of each line.
| Example
1 |
|
Write
the equation for a line with slope 8 and y-intercept 6.
y = 8x + 6 |
|
| Example
2 |
Write
the equation for the line containing the points (2, –2) and
(6, 0).
m =(0 +
2) / (6 - 2) = 2/4 = 1/2
|
|
y
= (1/2)x + b |
|
–2
= (1/2)(2) + b |
|
–2
= 1 + b |
|
–3
= b |
|
y
= (1/2)x – 3 |
Part II: The Point-Slope Equation
Write the equation of each line.
| Example
1 |
|
A
line with a slope 7 that contains the point (3, 4).
y – 4 = 7(x – 3), or
y – 4 = 7x – 21
y = 7x – 17 |
|
| Example
2 |
A
line containing the points (5, 7) and (2, 6).
First, find the slope. |
|
m
= (7 - 6) / (5 - 2) = 1/3 |
|
The
equation is
y – 7 = (1/3)(x –
5), or |
|
y
– 7 = (1/3)x – (5/3) |
|
y
= (1/3)x +
(16/3) |
|
| Example
3 |
A
graph of a line going through the points (–3, –1) and
(2, 1).
First, find the slope. |
|
m
= (1 + 1) / (2 +3) = 2/5 |
|
The
equation is
y – 1 = (2/5) (x – 2), or |
|
y
– 1 = (2/5)x
– (4/5) |
|
y
= (2/5)x
+ (1/5) |
|
Check
the graph by noticing that the slope is 2/5 and the y-intercept appears to be
1/5. |
Take class notes.
Before starting your homework, rework the
examples that are illustrated in this section of your textbook and the
examples that I demonstrated in class.
Then do your homework.
Write down questions (examples or concept
that you do not understand).......then.............. Ask these questions
in class.
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