Answer
$0.09x^2-0.96y+2.56y^2$
Work Step by Step
Using $(a+b)^2=a^2+2ab+b^2$ or the square of a binomial, the given expression, $
(0.3x-1.6y)^2
,$ is equivalent to
\begin{array}{l}\require{cancel}
(0.3x)^2+2(0.3x)(-1.6y)+(-1.6y)^2
\\\\=
0.09x^2-0.96y+2.56y^2
.\end{array}