(4x² - 2xy + y²) + (- 8x² -9xy – y²) + (x² + xy -8y²)

Answer 1

(4X^2-2XY+Y^2)+(-8X^2-9XY-6Y^2)+(X^2+8XY-8Y^2).

Combine like-terms:
-3X^2 - 3XY - 8Y^2.