[tex]0.01x^4+y^2-0.2x^2y=\\\\= 0.01x^4-0.2x^2y+y^2 =\\\\=\Big(0.1x^2\Big)^2-2\cdot0.1x^2\cdot y+\Big(y\Big)^2=\\\\=\boxed{\bf \Big(0.1x^2-y\Big)^2}[/tex]
That would be
(0.1x^2 - y)^2
Check:-
If we expand this (0.1x^2 - y)(0.1x^2 - y)
it = 0,01x^4 - 0.1x^2y - 0.1x^2y + y^2
= 0.01x^4 + y^2 - 0.2x^2y
