Answer
$(0.5t+0.4)(0.5t-0.4)$
Work Step by Step
Using the factoring of the difference of $2$ squares which is given by $a^2-b^2=(a+b)(a-b),$ the given expression, $
0.25t^2-0.16
,$ is equivalent to
\begin{align*}
&
(0.5t)^2-(0.4)^2
\\&=
(0.5t+0.4)(0.5t-0.4)
.\end{align*}