x^2+2xy+y^2
16x^2+48xy+36y^2
4x^2+4xy+y^2
a^2+2ab+b^2
9x^2+6xy+y^2
(a+b)^2
(4x+6y)^2
(3x+y)^2
(x+y)^2
(2x+y)^2
