Answer
$-\left(\dfrac{1}{4}s+1\right)\left(\dfrac{1}{4}s-1\right)$
Work Step by Step
Factoring $
-1
,$ the given expression, $
-\dfrac{1}{16}s^2+1
,$ is equivalent to
\begin{align*}
-\left(\dfrac{1}{16}s^2-1\right)
.\end{align*}
Using the factoring of the difference of $2$ squares which is given by $a^2-b^2=(a+b)(a-b),$ the expression above is equivalent to
\begin{align*}
&
-\left[\left(\dfrac{1}{4}s\right)^2-(1)^2\right]
\\\\&=
-\left[\left(\dfrac{1}{4}s+1\right)\left(\dfrac{1}{4}s-1\right)\right]
\\\\&=
-\left(\dfrac{1}{4}s+1\right)\left(\dfrac{1}{4}s-1\right)
.\end{align*}
