Question

What
should be
added
to
x² + xy + y
to obtain
2x^2
+ 3xy​

Answer 1

Let the polynomial added be 's'.

$s + ( {x}^{2} + xy + y) = {2x}^{2} + 3xy \\ s = {2x}^{2} + 3xy - {x}^{2} - xy - y \\ s = {x}^{2} + 2xy - y$

Therefore,

x^2 + 2xy - y

should be added .