/ 2 2\ (x + y)*(x + y) - \x + 3*y /
(x + y)*(x + y) - (x^2 + 3*y^2)
1*(x - y)*(y + 0)
(1*(x - y))*(y + 0)
2 2 2 (x + y) - x - 3*y
(x + y)^2 - x^2 - 3*y^2
2 2 2 (x + y) - x - 3*y
(x + y)^2 - x^2 - 3*y^2
2 2 2 (x + y) - x - 3*y
(x + y)^2 - x^2 - 3*y^2
2 2 2 (x + y) - x - 3*y
(x + y)^2 - x^2 - 3*y^2