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    Show that... log(base a)x^10 - 2log(base a)(x^3/4) = 4log(base a)(2x)
    I can only get close to the answer but not the actual I don't think I fully understand the rules. Help would be appreciated my exams on Friday


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    (Original post by Bethj1234)
    Show that... log(base a)x^10 - 2log(base a)(x^3/4) = 4log(base a)(2x)
    I can only get close to the answer but not the actual I don't think I fully understand the rules. Help would be appreciated my exams on Friday


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    Do you know the following rules:

    a\log_c b = \log_c b^a

    \log_c a - \log_c b = \log_c \frac{a}{b}
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    Yes I do! But I can't seem to apply them correctly to this question


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    (Original post by Bethj1234)
    Yes I do! But I can't seem to apply them correctly to this question


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    First, try applying

    a\log_c b = \log_c b^a

    to all the terms in the equation.
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    (Original post by Bethj1234)
    Show that... log(base a)x^10 - 2log(base a)(x^3/4) = 4log(base a)(2x)
    I can only get close to the answer but not the actual I don't think I fully understand the rules. Help would be appreciated my exams on Friday


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    Wait. I think you have not typed the question correctly. Try substituting a value for x and LHS is not equal to RHS.
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    (Original post by Vorte)
    Wait. I think you have not typed the question correctly. Try substituting a value for x and LHS is not equal to RHS.
    You're supposed to find a value for x, obviously substituting a random x value isn't going to work...
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    I have done but I end up with log(base a)x^10 - log(base a)(x^6/16). It's he fraction I'm struggling with. I tried to make it not a fraction like you'd do with 1/x^2 becoming x^-2 but I'm not sure how to do it x on top.


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    Does this work? I've probably done it wrong... ;L

    Where did you find this question? Seems too complex to come up on Friday.
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    I think you may have read part of the question wrong, also it only says show that! Solving for x would be too nasty to come up. Here's the question


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    Oh and the question is from june 2007 paper!


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    Here you are:
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    (Original post by spiruel)
    Here you are:
    Why has the sign changed in the second step from "-" to a "+"
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    (Original post by Hi, How are you ?)
    Why has the sign changed in the second step from "-" to a "+"
    Log rule - the minus 2 has been put as a power for (x^3/4). You have you interpret minuses as plussing a minus... If that makes sense. Basically, revise log rules so you're sure.

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    (Original post by Bethj1234)
    I think you may have read part of the question wrong, also it only says show that! Solving for x would be too nasty to come up.

    You didn't put brackets around the X^3/4 in your first post. That's why I misread it! You should have wrote it as (x^3)/4.

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    Ah it's so simple thank you! I didn't realise if you had a coefficient infront of the x that you had to take the 4th root of 16 to make it 4loga(2x) thought it was just left as 16


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