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Homework Help: Help with A level logarithms

  1. Sep 25, 2006 #1
    Hi

    I need some help!

    Doing A'level logarithms and am stuck.:rolleyes:

    log3(x-1)=log8(x+1)

    So far, I have done these steps...
    (x-1)log3=(x+1)log8
    xlog3-log3=xlog8+log8
    xlog3-xlog8-log3-log8

    Not sure what to do next to get the solution for x. Everything I do gets the wrong answer. I need an explanation in simple terms!

    Any help greatly appreciated!!!
     
  2. jcsd
  3. Sep 25, 2006 #2

    HallsofIvy

    User Avatar
    Science Advisor

    Do you mean log(3(x-1)), log3(x-1) or log 3x-1?
    (If you can't do subscripts or superscripts, use log_3(x-1) or log 3^(x-1).)

    Okay, it must be log(3x-1)= log(8x+1)

    Whoops, what happened to the "="?? I assume you meant
    xlog(3)- xlog(8)= log(8)- log(3)

    xlog(3)- xlog(8)= log(8)- log(3)
    x(log(3)- log(8))= log(8)- log(3)
    x= (log(8)- log(3))/(log(3)- log(8))
     
    Last edited by a moderator: Sep 25, 2006
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