Объяснение:

[tex](x - y + 2)(x + y + 2) = ((x + 2 )- y)((x + 2 )+ y) = {(x + 2)}^{2} - {y}^{2} [/tex]

[tex](1 + x + y)(1 - x - y) = (1 + (x + y))(1 - (x + y)) = {1}^{2} - {(x + y)}^{2} [/tex]

[tex](a - b + c)( a+ b- c) = (a - (b - c))(a + (b - c) = {a}^{2} - {(b - c)}^{2} [/tex]

Разность квадратов: а² - b² = (a-b)(a+b)

з) (х-у+2)(х+у+2) = (х+2 - у)(х+2 + у) = (х+2)² - у²

и) (1+х+у)(1-х-у) = (1 + х+у)(1 - (х+у)) = 1 - (х+у)²

к) (а-b+c)(a+b-c) = (a - (b-c))(a + b-c) = a² - (b-c)²