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    heya i would be gratefl if anyone could help me out with these questions

    1)x2(squared)-3x-5=0

    2)2x2-7=4x

    3)4x2-x=8

    4)15-6x-2x2=0

    basically these do go into fractions and i kind of got confused when the teacher was explaining it, he did a funny methods i hadnt been taught

    Any help much appreciated
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    The methods are exactly the same whether you're using fractions or not.

    If you have something like 3x^2+4x+1=0 then you can take out the factor of 3 to get 3 \left( x^2 + \dfrac{4}{3}x + \dfrac{1}{3} \right) = 0. Then you can complete the square on what's inside the bracket separately, and multiply through by 3 at the end.

    If the coefficient of x^2 is negative, multiply through by -1 as well.
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    Thank you , see i was going wrong because i got the denominator and numerator wrong thanks, do you always put b(second digit) before a(first digit) in turns on the numerator
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    (Original post by nuodai)
    The methods are exactly the same whether you're using fractions or not.

    If you have something like 3x^2+4x+1=0 then you can take out the factor of 3 to get 3 \left( x^2 + \dfrac{4}{3}x + \dfrac{1}{3} \right) = 0. Then you can complete the square on what's inside the bracket separately, and multiply through by 3 at the end.

    If the coefficient of x^2 is negative, multiply through by -1 as well.
    This isn't my thread but can I borrow you a second?
    I've got to complete 5x^2 + x -3 and i've got to 5 ( x^2 + \dfrac{1}{5}x - \dfrac{3}{5} ) and now i'm kinda stuck...
    can you tell me what I do next please, thankyou
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    (Original post by emma363)
    This isn't my thread but can I borrow you a second?
    I've got to complete 5x^2 + x -3 and i've got to 5 ( x^2 + \dfrac{1}{5}x - \dfrac{3}{5} ) and now i'm kinda stuck...
    can you tell me what I do next please, thankyou
    Look at x^2 + \dfrac{1}{5}x - \dfrac{3}{5} separately and complete the square on that in exactly the same way that you normally would -- don't let the fractions confuse you. Then put it back into the equation (i.e. multiply through by the 5 that you took out) and you're done.
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    (Original post by nuodai)
    Look at x^2 + \dfrac{1}{5}x - \dfrac{3}{5} separately and complete the square on that in exactly the same way that you normally would -- don't let the fractions confuse you. Then put it back into the equation (i.e. multiply through by the 5 that you took out) and you're done.
    okay cheers
 
 
 
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