Question

( -X² + 2XY + Y² - 2) + (X² - 2XY + Y² + 1) =

Answer 1

$- {x}^{2} + 2xy + {y}^{2} - 2 + {x}^{2} - 2xy + {y}^{2} + 1 \\ 2 {y}^{2} - 1 = 0 \\ {y}^{2} = \frac{1}{2} \\ y = \sqrt{0.5} \\ y = 0.71$