Question

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

16-x^2+2xy-y^2

Answer 1

1) \(=\left(x^2-4xy+y^2\right)-4=\left(x-2y\right)^2-4=\left(x-2y-2\right)\left(x-2y+2\right)\)

2) \(=16-\left(x^2-2xy+y^2\right)=16-\left(x-y\right)^2=\left(4-x+y\right)\left(4+x-y\right)\)

Answer 2

x^2-4xy+4y^2-4=(x^2-4xy+4y^2)-4=(x-y)^2-4=(x-y-2)(x-y+2)                                                  16-x^2+2xy-y^2=16-(x^2-2xy+y^2)=16-(x-y)^2=(4-x+y)(4+x-y)