Factorise $x^2+0.9x+0.2$x2+0.9x+0.2 into the form $\left(x+\editable{}\right)\left(x+\editable{}\right)$(x+)(x+).

Factorise the following expression:

$18-8t^2$18−8t2.

$x^2-y^2-x-y$x2−y2−x−y