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Math Help - Quadratic Equations By Factorising

  1. #1
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    Quadratic Equations By Factorising

    Can anyone solve the following Quadratic equation by using factorising?

    2xSquared - 5x - 7 = 0

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  2. #2
    Bar0n janvdl's Avatar
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    Quote Originally Posted by duckegg911 View Post
    Can anyone solve the following Quadratic equation by using factorising?

    2xSquared - 5x - 7 = 0

    Cheers
    2x^2 - 5x - 7 = 0

    (2x - 7)(x + 1 ) = 0

    x = \frac{7}{2}

    OR

    x = -1
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  3. #3
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    Quote Originally Posted by janvdl View Post
    2x^2 - 5x - 7 = 0

    (2x - 7)(x + 1 ) = 0

    x = \frac{7}{2}

    OR

    x = -1
    Many Thanks for the reply, is there any chance you can explain the steps?

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  4. #4
    Bar0n janvdl's Avatar
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    Quote Originally Posted by duckegg911 View Post
    Many Thanks for the reply, is there any chance you can explain the steps?

    Cheers
    You don't know how to factorise?
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  5. #5
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    Quote Originally Posted by janvdl View Post
    You don't know how to factorise?
    The questions are to help my son, so no i dont maths isnt my strong point im afraid
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  6. #6
    Bar0n janvdl's Avatar
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    Quote Originally Posted by duckegg911 View Post
    The questions are to help my son, so no i dont maths isnt my strong point im afraid
    Does he know how to factorise?

    If he does, he simply needs to find the value of x in each bracket seperately after factorising, so that one of the brackets is equal to 0.

    In other words:

    If we had (x - 3)(x + 4) = 0

    Then for the first bracket  x - 3 = 0 and for the second bracket x + 4 = 0
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  7. #7
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    Quote Originally Posted by janvdl View Post
    Does he know how to factorise?

    If he does, he simply needs to find the value of x in each bracket seperately after factorising, so that one of the brackets is equal to 0.

    In other words:

    If we had (x - 3)(x + 4) = 0

    Then for the first bracket  x - 3 = 0 and for the second bracket x + 4 = 0
    now i am confused - SORRY
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  8. #8
    Bar0n janvdl's Avatar
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    Quote Originally Posted by duckegg911 View Post
    now i am confused - SORRY
    Is it possible for your son to sit with you and look at the explanations?

    If ONE of the brackets = 0 then it will satisfy the equation. Then we only need to find another value for x to get the second bracket equal to 0 too.
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  9. #9
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    Quote Originally Posted by janvdl View Post
    Is it possible for your son to sit with you and look at the explanations?

    If ONE of the brackets = 0 then it will satisfy the equation. Then we only need to find another value for x to get the second bracket equal to 0 too.
    Ok thats starting to make sense now, the factorising bit.
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  10. #10
    Bar0n janvdl's Avatar
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    Quote Originally Posted by duckegg911 View Post
    Ok thats starting to make sense now, the factorising bit.
    So is there any other part where you feel you could benefit from a bit more explaining?
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  11. #11
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    Quote Originally Posted by duckegg911 View Post
    The questions are to help my son, so no i dont maths isnt my strong point im afraid
    Does your son have a set of class notes or tetxbook that covers factorising?
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  12. #12
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    Final Answer

    Quote Originally Posted by janvdl View Post
    So is there any other part where you feel you could benefit from a bit more explaining?
    is the final answer to solving this quadratic equation

    2xsquared - 12x -7
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  13. #13
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    Quote Originally Posted by duckegg911 View Post
    is the final answer to solving this quadratic equation

    2xsquared - 12x -7
    See this thread.
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