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    From Jan 05 Paper

    b) log2 (2x+1) = log2 x = 2

    log2 (2x+ 1 ) / x = 2

    This is the part i dont get

    2x + 1/ x = 2^2 = 4

    How do you get rid of the log2 and get 4 on the other side, can someone please explain that?

    and How does the change of base rule turn 6logx 5 into 6/log5 x


    thank you so much, i dont understand these at all so can you please explain it as fully as possible, much appreciated
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    When you have something of the form:

    logab = c, then you get:

    ac = b

    It's pretty much the fundemental rule of logs.
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    for the first part , to get rid of log2 you do 2(to the power of) to both sides

    so 2^log2(2x-1/x) just = (2x-1/x) and 2^2 = 4

    not sure for part 2
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    Change of base...

    6logx5 = 6[log55 / log5x] = 6/log5x

    Generally, logab = logcb / logca
 
 
 
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Updated: June 18, 2005
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