Answer
$f(x)=|x-1|\sqrt[]{5}$
Work Step by Step
Using the properties of radicals, the given equation, $
f(x)=\sqrt[]{5x^2-10x+5}
,$ simplifies to
\begin{array}{l}\require{cancel}
f(x)=\sqrt[]{5(x^2-2x+1)}
\\\\
f(x)=\sqrt[]{5(x-1)^2}
\\\\
f(x)=\sqrt[]{(x-1)^2\cdot5}
\\\\
f(x)=|x-1|\sqrt[]{5}
\end{array}