Question

Разложите на множители 9-x^2-2xy-y^2​

Answer 1

$9 - {x}^{2} - 2xy - {y}^{2} = \\ 9 - ( {x}^{2} + 2xy + {y}^{2} ) = 9 - (x - y {)}^{2} = \\(3 - (x + y)) \times (3 + (x + y) = \\ (3 - x - y)(3 + x + y)$

Answer 2

= 9 - ( x² + 2xy + y²) = 9 - ( x + y )² = ( 3 - x - y)(3 + x + y )