Answer
1
Work Step by Step
If $b\gt0$ and $b\ne1$, then $y=log_{b}x$ means $x=b^{y}$ for every $x\gt0$ and every real number $y$.
Therefore, $log_{7}1=0$. We know this, because $7^{0}=1$. In general, any nonzero real number raised to the power of 0 will have a value of 1.