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mogilem

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- Thread starter mogilem
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mogilem

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- #2

Office_Shredder

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[tex] \frac{ y_2-y_1}{x_2-x_1} = m [/tex]

where m is the slope of the line. In particular if I tell you the slope of the line and a point on it, let's say the slope is 3 and (1,5) is a point on the line, then if (x,y) is on the line it must satisfy

[tex] \frac{y-5}{x-1} = 3 [/tex]

where 3 is the m above, (1,5) is the [itex] (x_1,y_1)[/itex] above and (x,y) is the [itex] (x_2,y_2)[/itex] above. This equation is the point slope form of the line.

- #3

Mark44

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The slope-intercept form uses the slope and y-intercept.

From (y - 5)/(x - 1) = 3, multiply both sides by x - 1 to get y - 5 = 3(x - 1) = 3x - 3. Add 5 to both sides to get y = 3x - 3 + 5, or

y = 3x + 2

Here the slope is 3 (as before) and the y-intercept is 2, which means that the line goes through (0, 2).

- #4

mogilem

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- #5

Office_Shredder

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What Office_Shredder described is actually thepoint-slopeform of the equation of a line

OK, I obviously need to get more sleep

- #6

mogilem

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