Answer:
[tex](x - y + 2) \times (x + y - 2)[/tex]
Step-by-step explanation:
[tex] {x}^{2} - {y}^{2} + 4y - 4[/tex]
➡️ [tex] {x}^{2} - ( {y}^{2} - 4y + 4)[/tex]
➡️ [tex] {x}^{2} - (y - 2 {)}^{2} [/tex]
➡️ [tex](x - (y - 2)) \times (x + (y - 2))[/tex]
➡️ [tex](x - y + 2) \times (x + y - 2)[/tex]