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Math Help - circle formula

  1. #1
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    circle formula

    Please help find the center and radius of a circle
    4x^2 + 8y^2 - 12x + 16y + 18 = 0
    4 (x^2 - 3x + (3/2)^2) + 8 (y^2 + 2y +1) = -18 + 9 + 8
    4 (x-(3/2))^2 + 8 (y + 1)^2 = -1

    What do I do then?
    Thank you
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  2. #2
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    Quote Originally Posted by oceanmd View Post
    Please help find the center and radius of a circle
    4x^2 + 8y^2 - 12x + 16y + 18 = 0
    4 (x^2 - 3x + (3/2)^2) + 8 (y^2 + 2y +1) = -18 + 9 + 8
    4 (x-(3/2))^2 + 8 (y + 1)^2 = -1

    What do I do then?
    Thank you
    There is a typo in the original question since there's clearly no coordinate (x, y) that satisifes 4x^2 + 8y^2 - 12x + 16y + 18 = 0.

    Note: The fact that you think it's meant to be a circle means that the coefficient of x^2 and y^2 has to be the same ..... This is NOT currently the case.
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    Thank you

    Thank you very mucch
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  4. #4
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    What is correct is that the "graph" of that relation is the empty set.
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