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Math Help - equation of a straight line.

  1. #1
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    equation of a straight line.

    The straight line passing through the point P(2,1) and the point Q(k,11) has gradient - \frac{5}{12}

    (a) Find the equation of the line in terms of x and y only.
    (b) Determine the value of k


    Not sure how to go about doing this question.
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  2. #2
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    Quote Originally Posted by Tweety View Post
    The straight line passing through the point P(2,1) and the point Q(k,11) has gradient - \frac{5}{12}

    (a) Find the equation of the line in terms of x and y only.
    (b) Determine the value of k

    Not sure how to go about doing this question.
    Hi Tweety,

    Let's use the point-slope form of the linear equation: y-y_1=m(x-x_1).

    y-1=-\frac{5}{12}(x-2)

    If you have to convert this equation to slope-intercept or standard form, I'll assume you can handle that task.

    As far as finding k, let's set up the slope formula with k in it like this:

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

    \frac{-5}{12}=\frac{11-1}{k-2}

    \frac{-5}{12}=\frac{10}{k-2}

    -5(k-2)=120

    k-2=-24

    k=-22
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