Results 1 to 2 of 2

Math Help - Logarithm Help: Solve for x.

  1. #1
    Newbie
    Joined
    Oct 2009
    Posts
    1

    Exclamation Logarithm Help: Solve for x.

    I need to solve for x.

    8^(log_2(x)) - 25^(log_5(x)) = 4x - 4

    please can someone tell me how to solve this. All i have managed to do is prove it....but not solve for it.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor Amer's Avatar
    Joined
    May 2009
    From
    Jordan
    Posts
    1,093
    Quote Originally Posted by lockdout View Post
    I need to solve for x.

    8^(log_2(x)) - 25^(log_5(x)) = 4x - 4

    please can someone tell me how to solve this. All i have managed to do is prove it....but not solve for it.
    ok

    A^{log_A (x) } = x you should know this ok

    8^{\log _2 x} - 25^{\log _5 x} = 4x-4

    8=2^3 , 25 = 5^2 so

    2^{(3\log _2 x )} - 5^{(2\log _5 x)} = 4x-4

    \left(2^{\log _2 x}\right)^3 - \left(5^{\log _5 x}\right)^2 =4x-4

    x^3 - x^2 = 4x-4

    x^3-x^2 -4x+4 = 0 this for you
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. How do you solve this logarithm?
    Posted in the Algebra Forum
    Replies: 3
    Last Post: November 14th 2010, 07:14 AM
  2. Solve the logarithm.
    Posted in the Pre-Calculus Forum
    Replies: 1
    Last Post: January 22nd 2010, 01:12 PM
  3. Solve for x logarithm
    Posted in the Algebra Forum
    Replies: 2
    Last Post: December 17th 2008, 07:10 AM
  4. Solve Logarithm
    Posted in the Algebra Forum
    Replies: 3
    Last Post: October 28th 2008, 12:44 PM
  5. Logarithm - Solve for X
    Posted in the Algebra Forum
    Replies: 11
    Last Post: April 12th 2008, 10:05 PM

Search Tags


/mathhelpforum @mathhelpforum