Answer:
Log base 2 of 6 over log base 2 of 3
Step-by-step explanation:
In order to make a change of base of a logarithm, we apply this principle:

Where:
a: current base of the logarithm [in this case a = 3]
b: argument of the logarithm [in this case b = 6]
c: new base of the logarithm [in this case c = 2]
Applying this principle in this exercise, we have:

This quotient of logarithms can be expressed as:
Log base 2 of 3 over log base 2 of 6