SOLUTION: could you help me about this?:) log(3,log(4,log(5,x)))=0

We use this principle:

The logarithmic equation  may be written
as the exponential equation 

So let's let 

Then



becomes the log equation:



which by the above principle (in red) may be written as the
exponential equation:

 or 

And since we let , then



This time we let , and
that becomes:



Then we use the above same principle in red again on that
logarithmic equation, and we get the exponential equation:

 or 

Since we let , 



then we use that same principle again on that logarithmic
equation, and we get the exponential equation



thus



Edwin