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Homework Help: Logarithms help

  1. Dec 8, 2011 #1
    1. The problem statement, all variables and given/known data
    Solve the simultanious equations
    [tex] 2log_2y = log_43 + log_2x [/tex]
    [tex]3^y = 9^x [/tex]

    3. The attempt at a solution
    [tex] 3^y = (3^2)^x [/tex]
    [tex] y = 2x [/tex]

    [tex]2log_2 x + 2log_2 2 = log_2 \sqrt{3} + log_2 x[/tex]
    [tex]log_2 x = log_2 \frac{\sqrt{3}}{4}[/tex]

    No idea what to do from where, what does x equals?
    Last edited by a moderator: Dec 8, 2011
  2. jcsd
  3. Dec 8, 2011 #2
    Correct up to now.
    The only steps that remain to be done is to use

    2log(...) = log[(...)[itex]^{2}[/itex]] and

    logu + logv = log (uv)
  4. Dec 8, 2011 #3


    Staff: Mentor

    If logax = logay, then x = y.
  5. Dec 8, 2011 #4
    Ah okay, thank you guys.
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