We can estimate the answer before we start to be somewhere between 2 and 3, because 32 = 9 and 33 = 27. But how do we find the answer?

First we take the logarithm of both sides of the given equation:

log 3x = log 12.7

Now, using the 3rd log rule

logb (xn) = n logb x,

we have:

x log 3 = log 12.7

Now divide both sides by log 3:

x = (log 12.7)/(log 3)

= 2.3135

Is it correct? Checking in the original question, we have: 32.3135 = 12.7. Checks okay. Also, our answer is between 2 and 3 as we estimated before.