So we have the equation

, and we want to solve for

.
First, we are going to apply the log of a power rule:



Next, we are going to divide both sides of the equation by

:



Last but not least, we can use a calculator to evaluate the right hand side of the equation:


We can conclude that the solution of our logarithmic function is

. I don't know who told you that the correct answer is 8, but they is wrong.