Question

factorise x^2-4x+4y-y^2

Answer 1

$Heya$‼


$x^2-4x+4y-y^2$

$Rearranging:-$

$x^2-y^2-4x+4y$


$As\:we\:know,$

$a^2-b^2=(a+b)(a-b)$


$Now,back\:to\:your\:question.$

$=(x+y)(x-y)-4(x-y)$

$=(x+y-4)(x-y)$

Answer 2

Answer:

Given (x - y)^2 - 4(x - y) - 45 can be written as

         x^2 - 2xy - 4x + y^2 + 4y - 45

        (x - y - 9) ( x - y + 5)

       x - y = 9 (or) x - y = -5.

Step-by-step explanation: