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Homework Help: How do I simplify this fraction?

  1. Sep 14, 2011 #1
    1. The problem statement, all variables and given/known data


    Simplify the following expression by rewriting it as a single simple fraction in simplest form:


    LUZVL.gif



    2. Relevant equations

    not much just factoring and solving for P



    3. The attempt at a solution

    I tried to factor the fractions by multiplying the denominators with the numerators and after much writing on paper I came up with : (p+5)/(p^2-16) , I also came up with : (fp^2+p)/(p^3-16p)

    I'm stumped here as to how much I have to factor or simplify or even even I did it right?
     
  2. jcsd
  3. Sep 14, 2011 #2
    You are right in the sense that you need a common denominator..

    Would this help?

    5/(p+4) - 5/p(p-2) + 4/(p-4)(p+4)
     
  4. Sep 14, 2011 #3
    it's supposed to be "5/p(p-4)" but I've done it with ALOT of writing, this stuff fills up your page fast doesn't it?
     
  5. Sep 14, 2011 #4
    Well if you got it, who cares? Haha
     
  6. Sep 14, 2011 #5

    Dick

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    It can. But 5/(p(p-4)) isn't right. Putting p=1 in your original expression I get 12/5. Putting p=1 into 5/(p(p-4)) gives -5/3. That isn't right. Is there a typo?
     
  7. Sep 14, 2011 #6
    I don't know dick but I got the answer figured out after doing some more thinking, if you guys want to see a solution just wolfram alpha it.. I didn't do it that way though..
     
  8. Sep 15, 2011 #7

    Mentallic

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    Well I hope you didn't get 5/(p(p-4)) as the answer, because it's not right!
     
  9. Sep 15, 2011 #8

    symbolipoint

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    Lowest Common Denominator is [itex] p(p+4)(p-4)[/itex].

    Multiply each rational term by 1 using the suitable factors from the LCD,
    [itex]\frac{5}{(p+4)}\frac{p(p-4)}{p(p-4)}-\frac{5}{p(p-4)}\frac{p+4}{p+4}+\frac{4}{(p+4)(p-4)}\frac{p}{p}[/itex]

    Perform the needed multiplications for the numerator and look for any further simplifications.
     
  10. Sep 15, 2011 #9
    nono! I said that because somone else wrote the wrong thing and stuff.
     
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