2x - x² + y² + 2y = -x² + 2x + y² + 2y
= -x(x - 2) + y(y + 2)
= -(x - 2)(x) + (y + 2)(y)
= (2 - x)(x) + (y + 2)(y)
= (2 - x)(x) + (y + 2)(y)