The logarithm of any number to a given base is equal to the index to which the base should be raised to get the given number.
The logarithm of a product is equal to the sum of the logarithms of its factors.
The logarithm of a fraction is equal to the difference between the logarithm of the numerator and the logarithm of the denominator.
The logarithm of a power of a number is equal to the logarithm of the number multiplied by the power.