Answer
$7^{\frac{1}{2}}=\sqrt 7$
Work Step by Step
We know that if $b\gt0$ and $b\ne1$, then $y=log_{b}x$ is equivalent to $x=b^{y}$ (where $x\gt0$ and $y$ is a real number).
Therefore, $log_{7}\sqrt 7=\frac{1}{2}$ can be written as the exponential equation $7^{\frac{1}{2}}=\sqrt 7$.