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Math Help - Expanding Brackets with a Fraction

  1. #1
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    Expanding Brackets with a Fraction

    Expanding Brackets with a Fraction-0846.jpg

    The answer is: 4x +8x +4x

    So clearly I have done this incorrectly as I put the answer as '4x^4 +8x +4x'

    You can probably guess what I've done wrong, as I thought I had to remove the fraction by multiplying all the terms by the denominator.
    It seems as though everything is multiplied as though the fraction isn't there. What am I supposed to do?
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  2. #2
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    Re: Expanding Brackets with a Fraction

    Quote Originally Posted by Katrena View Post
    Click image for larger version. 

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    The answer is: 4x +8x +4x

    So clearly I have done this incorrectly as I put the answer as '4x^4 +8x +4x'

    You can probably guess what I've done wrong, as I thought I had to remove the fraction by multiplying all the terms by the denominator.
    It seems as though everything is multiplied as though the fraction isn't there. What am I supposed to do?
    Good morning,

    you have to distribute the factor to the summands here:

    4x^2\left(\color{red}x+2+\frac1x \color{black}\right)=4x^2 \cdot \color{red}x + \color{black}4x^2 \cdot\color{red} 2 + \color{black}4x^2 \cdot \color{red}\frac1x \color{black} = \boxed{4x^3+8x^2+4x}
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  3. #3
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    Re: Expanding Brackets with a Fraction

    Okay, thanks for quick reply. So I guess I just put the 4x as a fraction, over a 1 and multiply with the 1/x...
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    Re: Expanding Brackets with a Fraction

    Quote Originally Posted by Katrena View Post
    Okay, thanks for quick reply. So I guess I just put the 4x as a fraction, over a 1 and multiply with the 1/x...
    Correct
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  5. #5
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    Re: Expanding Brackets with a Fraction

    It looks to me like the fraction is not really the problem. Ignoring the fraction you appear to be saying that for
    4x^2(x+ 2), you got 4x^4+ 8x^3. And that is not true!
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