9x+4y9x + 4y9x+4y^2 = 9x+4y9x + 4y9x+4y9x+4y9x + 4y9x+4y = 9x 9x + 9x 4y + 4y 9x + 4y 4y= 81x^2 + 36xy + 36xy + 16y^2= 81x^2 + 72xy + 16y^2
9x+4y9x + 4y9x+4y^2 = 9x+4y9x + 4y9x+4y9x+4y9x + 4y9x+4y = 9x 9x + 9x 4y + 4y 9x + 4y 4y
= 81x^2 + 36xy + 36xy + 16y^2
= 81x^2 + 72xy + 16y^2