title: How do you isolate variable "a" in this equation in PHP : log(20) = log(a) + 3b?
body: <p>My highschool years are far behind and I'm having trouble remembering how to isolate the "a" variable in this equation :</p>
  
  <p>ln(20) = ln(a) + 3 * b</p>
  
  <p>b = 0.4605</p>
  
  <p>From this website (last section, at the very bottom <a href="http://mathonweb.com/help_ebook/html/expoapps_3.htm" rel="nofollow">http://mathonweb.com/help_ebook/html/expoapps_3.htm</a>) : "Back-substituting b into either of the previous equations gives ln (a) = 4.377, and anti-logging gives a = 79.6"</p>
  
  <p>I know this is fairly simple and I just need a quick help!</p>
  
  <p>Thanks a lot for your time</p>
  
  <p>Joel</p>