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Math Help - Simplyfying rational expression

  1. #1
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    Simplyfying rational expression

    I had thought that the common denominator was x-1, but this gives a wrong answer...How do I do the following question correctly?

    3/x-1 - 1/x + 2

    It looked easy enough..
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  2. #2
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    Quote Originally Posted by Charchar View Post
    I had thought that the common denominator was x-1, but this gives a wrong answer...How do I do the following question correctly?

    3/x-1 - 1/x + 2

    It looked easy enough..
    Assuming that you meant to write \frac{3}{x-1}-\frac{1}{x+2}, I will say that the LCD is (x-1)(x+2)
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  3. #3
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    Whoops, I should have put 'dividers' or something up to distinguish between terms. I meant:

    (3/x-1)-(1/x)+(2)
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  4. #4
    No one in Particular VonNemo19's Avatar
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    Quote Originally Posted by Charchar View Post
    Whoops, I should have put 'dividers' or something up to distinguish between terms. I meant:

    (3/x-1)-(1/x)+(2)
    Isn't the case that \frac{1}{2} and \frac{1}{3} have different denominators? Analogously, isn't x-1 a different number than x? So, since they are different, don't we need a common denominator?

    What's the first thing that x and x-1 will go into? Isn't it x(x-1)?
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  5. #5
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    Yes, you are right, they are representations of different numbers. Thank you very much, this will prove very valuable on the test!
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