Answer
$ f(x) = (x-5)^2-32$
Work Step by Step
The conversion of the function to the standard vertex form is self explanatory. All mathematical steps are shown below. $$
\begin{aligned}
g(x) & = x^2-10 x-7\\
& = x^2-10 x+\left(\frac{10}{2}\right)^2 -7-\left(\frac{10}{2}\right)^2 \\
& =\left(x^2-10 x+5^2\right)-7-5^2 \\
& =(x-5)^2-32.
\end{aligned}
$$