Question

What should be subtracted from x + xy + y^2 to obtain 2x^2 + 3xy?​

Answer 1

Let "a" be added to x^2 + xy +y^2 to obtain 2x^2 + 3xy

So a = 2x^2 + 3xy - (x^2 + xy + y^2)

= 2x^2 + 3xy - x^2 -xy - y^2

= x^2 + 2xy - y^2.

So x^2 + 2xy - y^2 must be added.