Answer:
D. 5x^2 + 2y^2 + 12x + 5y
Step-by-step explanation:
6x + 2y + y^2 + 6x + 2y + y^2 + 4x^2 + x^2 + y
6x + 6x = 12x
12x + 2y + y^2 + 2y + y^2 + 4x^2 + x^2 + y
2y + 2y + y = 5y
12x + 5y + y^2 + y^2 + 4x^2 + x^2
y^2 + y^2 = 2y^2
2y^2 + 4x^2 + x^2 + 12x + 5y
4x^2 + x^2 = 5x^2
2y^2 + 5x^2 + 12x + 5y
5x^2 + 2y^2 + 12x + 5y
