Answer
$3-y$
Work Step by Step
Using the properties of radicals, the given expression, $
\sqrt{9-6y+y^2}
,$ simplifies to
\begin{array}{l}
\sqrt{(3-y)^2}
\\\\=
3-y
.\end{array}
Note that it is assumed that no radicand was formed by raising negative quantities to even powers. Thus, absolute value bars are not necessary.