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Adding and subtracting Rational Expressions

  1. Feb 14, 2007 #1
    I'm stuck on how to do this problem

    My attempt:


    the answer to the second one is 3x + 2/(x+2)(x-2)

    Can someone point out my mistake?
  2. jcsd
  3. Feb 14, 2007 #2
    When you said that:

    [tex]\frac{2}{x(x+2)} + \frac{x}{x(x-2)} = \frac{x^2-4}{(x+2))(x-2)}[/tex]

    That is incorrect (take x = 1 and you get -1/3 = 1).

    Also, just as a style note: you should write the fraction bar so that it extends over both the top and the bottom. (does that make sense?) For example, on your last line, you have a little bar below the 4, you should instead have a bar going from the start of the first 2x to the end of the last 2x. Unless of course you meant to write:
    [tex]2x - \frac{4}{(x+2)(x-2)} + x^2 + 2x[/tex]

    edit... also the "answer" you wrote is not correct.
    Last edited: Feb 14, 2007
  4. Feb 15, 2007 #3
    Alright, Thank you.
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