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    What method do you use when you have a quadratic such as 2x^2 -11x+5=0
    I can do basic factorisation when the quadratic is x^2
    I've seen people use different methods for the more complicated ones?
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    I use the belgian method. It works really well.
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    (Original post by PrincessParadox)
    What method do you use when you have a quadratic such as 2x^2 -11x+5=0
    I can do basic factorisation when the quadratic is x^2
    I've seen people use different methods for the more complicated ones?
    If you use the method where you think of factors of 5, which differ by 11, then it can still be applied to a problem like this. However, you need to multiply the constant by the coefficient of x^2 (not physically, just mentally), so you think of factors of 10, which differ by 11.

    Obviously, 10 and 1 do the job.

    So, 2x^2 - 11x + 5 = 0
    => 2x^2 - 10x - x + 5 = 0
    => (2x^2 - 10x) - (x - 5) = 0
    => 2x(x - 5) - 1(x - 5) = 0
    => (2x - 1)(x - 5) = 0
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    I almost always use the formula if the factorisation isnt obvious, cos it saves so much time.
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    just do loads of them and then you'll get really quick. It's much better than the formula.

    MB
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    In an exam question if it says factorise and you can't see how to do it, solve it with the formula and use the answers to come up with the contents of the brackets.

    Just a tip.

    Later Editing Note:
    Whoever gave me rep. for this post. Unfortunately you havent posted enough or got enough rep to make a difference (+ or -) to my reputation level. But remember me when you have. Thanks.
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    any other methods?
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    actually quite like alec's method now
 
 
 
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Updated: June 28, 2004
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