Results 1 to 2 of 2

Math Help - log equation

  1. #1
    Newbie
    Joined
    Feb 2009
    Posts
    18

    log equation

    Hi,

    I need a bit of help to solve a log equation. Any help is so much appreciated!

    I need to solve this logarithm for x:

    log3x81 = 2

    (where 3x is the base of the log)

    I was thinking of booting the log to get:

    81 = 3x^2

    but then what? or am I on the wrong track to solving.

    Thanks,

    Jim.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Senior Member topher0805's Avatar
    Joined
    Jan 2008
    From
    Vancouver
    Posts
    336
    Quote Originally Posted by jimstewart_NC View Post
    Hi,

    I need a bit of help to solve a log equation. Any help is so much appreciated!

    I need to solve this logarithm for x:

    log3x81 = 2

    (where 3x is the base of the log)

    I was thinking of booting the log to get:

    81 = 3x^2

    but then what? or am I on the wrong track to solving.

    Thanks,

    Jim.
    You are correct that:

    (3x)^2 = 81

    Now take the square root of both sides:

    3x = 9

    Divide both sides by 3:

    x = 3
    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