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Math Help - Slope Question! Help Please!

  1. #1
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    Slope Question! Help Please!

    Find the value of r so the line that passes through each pair has the given slope.

    1. (r,3), (5,9), m=2
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  2. #2
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    Just use the definition of a slope. Say that we have 2 points (x_1, y_1) and (x_2, y_2).

    The slope is given by: m = \frac{y_2 - y_1}{x_2 - x_1}

    Here: x_1 = r, \ y_1 = 3, \ x_2 = 3, \ y_2 = 9, \ m = 2

    Plug it all in and simply solve.
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  3. #3
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    The gradient of the line, m, is 2. Now remember when we have two points on a line we can find the gradient using this formula:

    m = \frac{y_1 - y_2}{x_1 - x_2}

    2 = \frac{3 - 9}{r - 5}

    \Rightarrow 2(r - 5) = -6

    Now solve for r.
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