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    Moderator Katsumi's Avatar
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    Logarithmic Question

    Hi All,

    I'm currently stuck on a logarithmic question that i've been attempting for most of an hour with 0 success. There are no answers releases yet & any help would be appreciated

    Question below



    My main point of confusion comes to what rule to apply first. Do i first have to solve Ln(10) & then isolate the logarithmic function by dividing the answer by 3?

    Note that i need to find the value "x"
    Last edited by Katsumi; 8 Mar 2017 at 10:19 PM.
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    Rambling Spirit
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    Re: Logarithmic Question

    Quote Originally Posted by Katsumi View Post
    Hi All,

    I'm currently stuck on a logarithmic question that i've been attempting for most of an hour with 0 success. There are no answers releases yet & any help would be appreciated

    Question below



    My main point of confusion comes to what rule to apply first. Do i first have to solve Ln(10) & then isolate the logarithmic function by dividing the answer by 3?
    Last edited by InteGrand; 8 Mar 2017 at 10:23 PM.

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    Magniloquent Member mreditor16's Avatar
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    Re: Logarithmic Question

    3*(logx(7))=ln(10)
    logx(7^3)=ln(10)
    logx(343)=ln(10)
    x^(logx(343))=x^(ln(10))
    343=x^(ln(10))
    343^(1/ln(10))=(x^(ln(10))^(1/ln(10))
    343^(1/ln(10))=x^((ln(10))*(1/ln(10))
    343^(1/ln(10))=x^(1)
    x=343^(1/ln(10))
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    Re: Logarithmic Question

    If you know that xlogxa = a, then after dividing both sides by 3, xlogx7 = xln10/3

    So, 7 = xln10/3

    Raising both sides by 3/ln10 gives x = 73/ln10

    Quote Originally Posted by Katsumi View Post
    Do i first have to solve Ln(10)
    This is your first misunderstanding. You can't 'solve' ln10 - this is just a number, like the number 200, you can't solve just that number.

    You will need to learn the log rules in order to solve any log problems. They are fundamental as they set the laws that govern what you can and can't do.

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    Moderator Katsumi's Avatar
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    Re: Logarithmic Question

    So this is the correct logic?

    equation provided in question
    3logx7 = ln10
    a * logbc = logb(c^a)
    logx7^3 = ln10
    logbc=a is equal to b^a = c
    x^ln10 = 7^3
    isolate x by raising both sides to 1/x^ln10
    x = (7^3)^1/ln10
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    Ancient Orator leehuan's Avatar
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    Re: Logarithmic Question

    Quote Originally Posted by Katsumi View Post
    So this is the correct logic?

    equation provided in question
    3logx7 = ln10
    a * logbc = logb(c^a)
    logx7^3 = ln10
    logbc=a is equal to b^a = c
    x^ln10 = 7^3
    isolate x by raising both sides to 1/x^ln10
    x = (7^3)^1/ln10
    Yep

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