# How do you solve logx+log(x+15)=2?

Feb 4, 2015

Supposing the base of the log being $10$ you can solve it by using:

So you get (using also the definition of logarithm):

Feb 4, 2015

There is an error.

The arguments of the logarithmics have to be positive.

So you had to put two condition:

$x > 0$
$x > - 15$

they drive us to $x > 0$.

So, one of the solution you found ($- 20$) is not acceptable!