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logarithm question, PLEASE HELP, i'd appreciate it!?

Use properties of logarithms to find the exact value of the expression log9 27 • log2 8

so i know that log 2 8 can be written log 2 2^3 thus equaling 3, but how do you solve log 9 27?

5 Answers

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  • iceman
    Lv 7
    9 years ago
    Favorite Answer

    log9 27 * log2 8

    = log(3^3)/log(3^2) * log(2^3)/log(2)

    = 3log(3)/2log(3) * 3log(2)/log2

    = 3/2 * 3 = 9/2

  • Anonymous
    9 years ago

    (property :-- log a N =z so N=a^z)

    log9 27=x

    27=9^x (using the above property)

    3^3=3^2x

    as the base are same i.e=3 so equating the powers

    3=2x

    x=3/2

    log2 8=y

    8=2^y (again using the property)

    2^3=2^y

    again base is same i.e 2 so equating the powers

    y=3

    log9 27 . log2 8=x*y=3/2*3=9/2

  • 9 years ago

    A scientific calculator can tell you that log (base 9) of 27 is 1.5.

    But if you remember that 3^2 = 9 and 3^3 = 27, then you can figure out the answer in your head:

    3/2 = 1.5

    The final answer to your question is 1.5 * 3 = 4.5

  • 9 years ago

    log9 27 is the solution of 9^x=27

    9=3^2 and 27=3^3

    so we get

    (3^2)^x=3^3

    that is

    3^(2x)=3^3

    hence 2x=3

    and x=1.5

    log9 27 = 1.5

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  • gile
    Lv 7
    9 years ago

    log_9 (27) = log_9 (9^3/2) = 3/2

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