Results 1 to 4 of 4

Math Help - Basic Logarithm Problem

  1. #1
    Newbie
    Joined
    Nov 2009
    Posts
    2

    Basic Logarithm Problem

    Alright, this one particular question is driving me nuts, I've tried it with many different approaches, but they keep producing undefined results. It's probably something simple that I'm overlooking, but if someone could help show me the proper approach to this, it would help a lot.

    9^(2x)=10^x

    **Edit** Sorry, the 2x is supposed to be a power of 9.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor
    skeeter's Avatar
    Joined
    Jun 2008
    From
    North Texas
    Posts
    12,139
    Thanks
    1013
    Quote Originally Posted by unk2100 View Post
    Alright, this one particular question is driving me nuts, I've tried it with many different approaches, but they keep producing undefined results. It's probably something simple that I'm overlooking, but if someone could help show me the proper approach to this, it would help a lot.

    9^(2x)=10^x

    **Edit** Sorry, the 2x is supposed to be a power of 9.
    9^{2x} = 10^x

    81^x = 10^x

    x = 0
    Follow Math Help Forum on Facebook and Google+

  3. #3
    -1
    e^(i*pi)'s Avatar
    Joined
    Feb 2009
    From
    West Midlands, England
    Posts
    3,053
    Thanks
    1
    Quote Originally Posted by unk2100 View Post
    Alright, this one particular question is driving me nuts, I've tried it with many different approaches, but they keep producing undefined results. It's probably something simple that I'm overlooking, but if someone could help show me the proper approach to this, it would help a lot.

    9^(2x)=10^x

    **Edit** Sorry, the 2x is supposed to be a power of 9.
    9^{2x} = (3^2)^{2x} = 3^{4x}

    3^{4x}=10^x

    Take logs

    4x\, log_{10}(3) = x

    x(4\,log_{10}3 - 1) = 0

    x = 0
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Newbie
    Joined
    Nov 2009
    Posts
    2
    wow, you guys are quick. Thanks.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Logarithm Problem
    Posted in the Pre-Calculus Forum
    Replies: 4
    Last Post: May 6th 2010, 09:22 AM
  2. basic logarithm question
    Posted in the Pre-Calculus Forum
    Replies: 3
    Last Post: February 5th 2010, 06:52 AM
  3. logarithm problem
    Posted in the Algebra Forum
    Replies: 3
    Last Post: May 9th 2009, 04:51 AM
  4. Logarithm problem
    Posted in the Math Topics Forum
    Replies: 5
    Last Post: May 12th 2008, 12:12 AM
  5. basic logarithm problem
    Posted in the Algebra Forum
    Replies: 1
    Last Post: March 16th 2008, 08:02 PM

Search Tags


/mathhelpforum @mathhelpforum