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Math Help - Solving a quadratic equation

  1. #1
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    Solving a quadratic equation

    30/x^2 = 1 - 7/x

    I know I need to multiply 30 by x and then 7 by x^2, but what do I need to do with the 1?

    Thanks
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  2. #2
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    Quote Originally Posted by Local_lunatic View Post
    30/x^2 = 1 - 7/x

    I know I need to multiply 30 by x and then 7 by x^2, but what do I need to do with the 1?

    Thanks
    Mutiply everything by x^2 and see what you get.
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  3. #3
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    Quote Originally Posted by ThePerfectHacker View Post
    Mutiply everything by x^2 and see what you get.
    30/x^2 = 1- 7/x
    30 = x^2 - 7x
    x^2 - 7x - 30 =0
    (x+3) (x-10) =0
    x=-3 or x=10

    How do you know to multiply it by x^2? Is there a rule or something to follow?

    Thanks
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  4. #4
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    Quote Originally Posted by Local_lunatic View Post
    30/x^2 = 1- 7/x
    30 = x^2 - 7x
    x^2 - 7x - 30 =0
    (x+3) (x-10) =0
    x=-3 or x=10

    How do you know to multiply it by x^2? Is there a rule or something to follow?

    Thanks
    Since there is an x^2 on the bottom of the fraction, to get it to disappear and have a simpler equation to work with, you multiply every term by it.
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  5. #5
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    Quote Originally Posted by Adrienne View Post
    Since there is an x^2 on the bottom of the fraction, to get it to disappear and have a simpler equation to work with, you multiply every term by it.
    Of course it is, I was thinking that it was x not x^2.. Sometimes I swear my brain isn't switched on!

    Thanks both of you for your help
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