Answer
Because $log_{b}1=0$
Work Step by Step
We are given that $log_{b}7=log_{b}(\frac{7}{1})=log_{b}7-log_{b}1$.
Although this seems counterintuitive, we know that $log_{b}7=log_{b}7-log_{b}1$, because $log_{b}1=0$ according to the properties of logarithms.
Therefore, $log_{b}7=log_{b}7-log_{b}1=log_{b}7-0=log_{b}7$.
