Results 1 to 5 of 5

Math Help - equation for x

  1. #1
    Junior Member
    Joined
    Mar 2007
    Posts
    25

    equation for x

    solve equation for x:

    12^(x - 7) =
    7

    can someone please help me with this?
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Newbie
    Joined
    Sep 2009
    Posts
    20
    The inverse function of exponentiation is a logarithm.
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Junior Member
    Joined
    Mar 2007
    Posts
    25
    thanks, but i'm still unfamiliar with what you mean.
    Follow Math Help Forum on Facebook and Google+

  4. #4
    A riddle wrapped in an enigma
    masters's Avatar
    Joined
    Jan 2008
    From
    Big Stone Gap, Virginia
    Posts
    2,551
    Thanks
    12
    Awards
    1
    Quote Originally Posted by darkblue View Post
    thanks, but i'm still unfamiliar with what you mean.
    Hi darkblue,

    This is what he means.

    Take the natural log of both sides and use this:

    \ln a^r=r \ln a,


    12^{x-7}=7

    \ln 12^{x-7}=\ln 7

    (x-7)\ln 12=\ln 7

    x-7=\frac{\ln 7}{\ln 12}

    x=\frac{\ln 7}{\ln 12}+7
    Follow Math Help Forum on Facebook and Google+

  5. #5
    Junior Member
    Joined
    Mar 2007
    Posts
    25
    thankyou so much!!
    it is much easier to understand when i have a visual.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Replies: 1
    Last Post: April 11th 2011, 01:17 AM
  2. Partial differential equation-wave equation - dimensional analysis
    Posted in the Differential Equations Forum
    Replies: 3
    Last Post: August 28th 2009, 11:39 AM
  3. Replies: 2
    Last Post: May 18th 2009, 12:51 PM
  4. Replies: 2
    Last Post: April 28th 2009, 06:42 AM
  5. Replies: 1
    Last Post: October 23rd 2008, 03:39 AM

Search Tags


/mathhelpforum @mathhelpforum