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    Solve the equation x^6 + 26x^3 -27=0
    i substituted x^6 for x^2,
    so i'm trying to factorise x^2+26x-27=0?? i cant seem to factorise it.
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    You're on the right track. You can factorise x^2+26x-27=0 by finding two numbers whose sum is 26x and whose product is -27x^2.
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    (Original post by Chelsea12345)
    Solve the equation x^6 + 26x^3 -27=0
    i substituted x^6 for x^2,
    so i'm trying to factorise x^2+26x-27=0?? i cant seem to factorise it.
    You can't find two numbers that multiply to give -27 and add to give 26 ?????
    By considering every positive integer starting at 1, Systematically make a list of factor pairs
    1 and -27
    3 and -9
    9 and -3
    Etc

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    (Original post by Chelsea12345)
    Solve the equation x^6 + 26x^3 -27=0
    i substituted x^6 for x^2,
    so i'm trying to factorise x^2+26x-27=0?? i cant seem to factorise it.
    It can be factorised. I don't really want to give you the answer, but 27 and 1.
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    (Original post by Chelsea12345)
    Solve the equation x^6 + 26x^3 -27=0
    i substituted x^6 for x^2,
    so i'm trying to factorise x^2+26x-27=0?? i cant seem to factorise it.
    You know, completing the square is always an option. You don't always have to give up just because you can't spot the shortcut.
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    if you can't spot the factors you could complete the square & solve ?
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    (Original post by RDKGames)
    You know, completing the square is always an option. You don't always have to give up just because you can't spot the shortcut.
    i wasn't aware that factorising is a shortcut and even so, i've been repeatedly trying to factorise the equation using different numbers for a quite a while before i posted the question. The thought of completing the score hasn't crossed my mind but implying that i'm giving up on the question is uncalled for.
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    for this example it would be quite hard to use the formula to solve, but completing the square is not too bad.
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    (Original post by emduck)
    It can be factorised. I don't really want to give you the answer, but 27 and 1.
    correction 27 and -1

    (Original post by gdunne42)
    You can't find two numbers that multiply to give -27 and add to give 26 ?????


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    (Original post by Emz99)
    correction 27 and -1
    I know. (x-1)(x+27)=0 x=1 or x=-27 but I just gave the factors that made up 27, I assumed they'd be able to work out the rest. I guess I should've probably said 27 and -1

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