Answer
$0.11x^4-1.7x^2-10$
Work Step by Step
Using the FOIL method, the given expression, $
(1.1x^2+5)(0.1x^2-2)
,$ is equivalent to
\begin{array}{l}\require{cancel}
1.1x^2(0.1x^2)+1.1x^2(-2)+5(0.1x^2)+5(-2)
\\\\=
0.11x^4-2.2x^2+0.5x^2-10
\\\\=
0.11x^4-1.7x^2-10
.\end{array}