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Math Help - Quick Finding Y Values Question (algebra 1)

  1. #1
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    Quick Finding Y Values Question (algebra 1)

    I have one homework question I can't seem to get it!! I'm looking for the answers thank you.


    It says, Find all values of Y such that the distance between (9,y) and (-4,6) is 17.


    Y=???


    *(Use a comma to seperate answers as needed. Type exact answers, using radicals as needed.)*

    THANK YOU SO MUCH
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  2. #2
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    use the distance formula ...

    d = \sqrt{(x_2 - x_1)^2 + (y_2 - y_1)^2}

    plug in your known values and solve for the missing value of y ... note that you will get two solutions.
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  3. #3
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    I'm looking for the answers thank you.
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  4. #4
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    We use the distance formula to find the distance between two points:
    d^2 = (x_2 - x_1)^2 + (y_2 - y_1)^2

    d = \sqrt{(x_2 - x_1)^2 + (y_2 - y_1)^2}

    Given the distance, a point (name it A), and the x-coordinate of another point (name it B), we can find the y-coordinate of B using the distance formula.

    d = 17
    A(-4,6) =  (x_2, y_2)
    B(9, y) = (x_1, y_1)

    (17)^2 = (-4 - 9)^2 + (6 - y)^2

    289 = 169 + 36 - 12y + y^2

    y^2 - 12y - 84 = 0

    Solve for y now. I will complete the square.

    y^2 - 12y + 36 - 36 - 84 = 0

    (y - 6)^2 = 120

    y - 6 = \pm\sqrt{120}

    y = 6\pm\sqrt{120}

    EDIT: It's all good.
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  5. #5
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    k thats wrong it said

    6+2[30

    6-2[30

    damnit.
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  6. #6
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    No it is not wrong.

    \sqrt{120} = \sqrt{4\cdot30} = 2\sqrt{30}
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