## Precalculus (6th Edition) Blitzer

The change-of-base property for logarithms allows us to write logarithms with base $b$ in terms of a new base $a$. Introducing base $a$, the property states that$$\log_bM=\frac{\log_aM}{\log_ab}.$$For example, $$\log_35=\frac{\log_25}{\log_23}$$