Logs

To solve a log, you write it as an exponent.  The standard log is logb x=a. To write it as an exponent, it is b^a=x.  Your b is your base, your a is your exponent, and the x is the number that the base and exponent are set equal to each other.  If no base is written for the log, it is implied to be 10.  If we have an ln, the base will always be e.  If b and x are equal then they cancel along with the log.  So for this problem, we have the base of the log as 2 and the exponent is x.  It is equal to 4, so we find common bases, which is 2.  Now we have 2 raised to the x and 2 raised to the 2.  Now you set the exponents equal to each other and solve for x and the answer ends up being x equals 2.