Question

what should be added to X square + xy + Y square to obtain 2 X square + 3 x y​

Answer 1

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

Rearrangement

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

collecting like terms

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

This is the answer this value. The value of z is the answer.

Answer 2

first subtract x square +xy+y from 2xsquare +3xy
(2x^2 +3xy)-(x^2 +xy +y)
=2x^2+3xy-x^2-xy-y
=x^2 +2xy -y