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    can somebody check if I did this correctly?



    I'm not sure if there's a mistake anywhere, I mean I checked it, but it seems really complicated with all the fraction work for what a looks like an easy question
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    You've missed out a cubic when you multiplied out that bracket of (4x+1)(x-2-x^2)

    I came out at the end with a cubic

    0 = 4x^3 + 4x^2 - 7x + 2
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    (Original post by frostyy)
    can somebody check if I did this correctly?
    I'm not sure if there's a mistake anywhere, I mean I checked it, but it seems really complicated with all the fraction work for what a looks like an easy question
    Check your expansion of (4x+1)(x-2-x^2), specifically your third term, what's 4x \times -x^2?

    Edit: ninjaed. :ninja: Sorry 403!
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    (Original post by frostyy)
    can somebody check if I did this correctly?
    You might notice immediately that there's something wrong because you have the square root of a negative number. This result will not occur in core mathematics.
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    (Original post by Zacken)
    Check your expansion of (4x+1)(x-2-x^2), specifically your third term, what's 4x \times -x^2?

    Edit: ninjaed. :ninja: Sorry 403!
    Nah your LaTeX makes everything look 10x nicer and clearer :yep:
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    (Original post by aymanzayedmannan)
    You might notice immediately that there's something wrong because you have the square root of a negative number. This result will not occur in core mathematics.
    To be fair, should have noticed right away when he computed the discriminant to check whether it was a perfect square or not and got -15.
 
 
 
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