College Algebra
Answer/Discussion to Practice Problems
Tutorial 25: Slope of a Line
 Answer/Discussion
to 1a
(2, -5) and (-1, -1) |
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*Plug in x and y values into slope formula
*Simplify
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Make sure that you are careful when one of
your values is negative and you have to subtract it as we did in line 2.
-5 - (-1) is not the same as -5 - 1 and 2 - (-1) is not the same as 2 -
1.
The slope of the line is -4/3.
Since the slope is negative, the line would fall (left to right). |
Answer/Discussion
to 1b
(7, 1) and (7, 2) |
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*Plug in x and y values into slope formula
*Simplify
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The slope of the line is undefined.
Since the slope is undefined, the line is vertical. |
Answer/Discussion
to 1c
(1, 7) and (-2, -2) |
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*Plug in x and y values into slope formula
*Simplify
|
Make sure that you are careful when one of
your values is negative and you have to subtract it as we did in line 2.
7 - (-2) is not the same as 7 - 2 and 1 - (-2) is not the same as 1 - 2.
The slope of the line is 3.
Since the slope is positive, the line would rise (left to right). |
Answer/Discussion
to 1d
(-1, -5) and (-4, -5) |
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*Plug in x and y values into slope formula
*Simplify
|
Make sure that you are careful when one of
your values is negative and you have to subtract it as we did in line 2.
-5 - (-5) is not the same as -5 - 5 and -1 - (-4) is not the same as -1
- 4.
The slope of the line is 0.
Since the slope is zero, the line is horizontal. |
Last revised on Jan. 16, 2010 by Kim Seward.
All contents copyright (C) 2002 - 2010, WTAMU and Kim Seward. All rights reserved.
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