Respuesta :

㏒(5x) = ㏒(2x + 9)
      5x = 2x + 9
    - 2x  - 2x
      3x = 9
       3     3
        x = 3
Your problem "solve log5x=log (2x+9)" is a simple problem to solve. 

5x-2x=9 

3x=9

x=3