Hello !
Answer:

Explanation:
We want to find the value of x that verifies the following equation :

Let's remember :

We can apply this property to our equation :

Let's factor the left side by x :

We can apply the previous property to put the 3 as an exponent in the log

Let's divide both sides by 2 :

Finally, let's divide both sides by log(8) :

Have a nice day ;)