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This should be easy

  1. Aug 21, 2008 #1
    I'm certain I'm missing something obvious .. again.

    I'm having trouble solving the following (using a pen and paper approach)

    [tex] \frac{ 3^{12} - 3^{10} }{ 3^{11} + 3^{10} } [/tex]

    I've tried logarithms (I've only covered those with base 10 so far, so any log_n approach is disqualified), messing around with the exponents, roots and factoring, but I cant seem to find a way to do this without actually calculating the individual values.

    Enlighten me, please.

    k
     
    Last edited: Aug 21, 2008
  2. jcsd
  3. Aug 21, 2008 #2

    Dick

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    Divide numerator and denominator by 3^10.
     
  4. Aug 21, 2008 #3

    HallsofIvy

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    Or (same thing really) factor out a 310: 311= 310*3 and 312= 310*9
    [tex]\frac{3^{12}- 3^{10}}{3^{11}- 3^{10}}= \frac{3^{10}(9- 1)}{3^{10}(3- 1)}[/tex]
     
  5. Aug 21, 2008 #4
    aaah, sweet relief.

    thank you.

    k
     
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