1. PF Contest - Win "Conquering the Physics GRE" book! Click Here to Enter
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Solving Exponential Equation

  1. Apr 12, 2009 #1
    1. The problem statement, all variables and given/known data

    3^x + x = 4

    solve for x.
    2. Relevant equations

    I'm thinking of using the logarithm laws. log(a.b) = log a + logb log(a/b) = log a - log b

    log(a^b) = bloga

    3. The attempt at a solution
    Well if I isolate the exponential
    3^x = 4-x

    take logs on both sides

    xlog3 = log(4-x)

    I can't seem to get the x out of the log.
  2. jcsd
  3. Apr 12, 2009 #2


    User Avatar
    Homework Helper

    You won't be able to find a solution algebraically. However the value for x is quite obvious. Take a good look at the equation in its original form.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook