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Homework Help: Logarithmic eqautions

  1. Jan 6, 2012 #1
    Having problems with these questions, what's putting me off is for example the first question, if the numbers 9 and 5 were the same I think I could do it. Do I have to get them to the same number or do I just multiply them?

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  2. jcsd
  3. Jan 6, 2012 #2
    For (1). Take log of both sides and use logarithm rules.

    That's about all the help I'm giving you right now. You make an effort now.
  4. Jan 6, 2012 #3


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    For (ii), multiply both sides by et. Let w = et, and rewrite the equation in terms of w. What does the resulting equation look like now?
  5. Jan 6, 2012 #4

    Ray Vickson

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    (i) lhs= 125*[9^3 *5^2]^x = 125* 18225^x
    rhs = 3^3*2^4/5^2 *[3^4/2/5^3]^x = (432/25)(81/250)^x.
    Thus, [18225*250/81]^x = (432/25)/125.

    (ii) Put x = exp(t) and see what you get.

    (iii) Put x = ln(i+2). First you need to decide if [itex] \ln(i+2)^6 [/itex] means [itex] \ln [(i+2)^6] [/itex] or [itex] [ \ln (i+2) ]^6 . [/itex]

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