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N00b here and i got a question (logarithms)

  1. Nov 21, 2003 #1
    Okay.
    "Solve the exponential equation with base a algebraically. Approximate the result to three decimal places."

    3^2x=80

    (fyi, the answer is ln80/2ln3 = 1.994)

    Don't understand how to solve, please help!
     
  2. jcsd
  3. Nov 21, 2003 #2

    jcsd

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    As you already have the answer and you want to understand the question, I think it's okay to take you through it step-by-step:

    32x = 80

    take the natural logarithm of both sides:

    ln 32x = ln 80

    use the rule ln xy = yln x:

    2xln 3 = ln 80

    2x = ln 80/ln 3

    x = ln 80/2ln 3
     
  4. Nov 21, 2003 #3
    Ah. Thanks alot! For future reference, how can i show the numbers being squared in the corner and small like you were able to
     
  5. Nov 21, 2003 #4

    jcsd

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