Question

4xy - x² - 4y^2 + z²​

Answer 1

Here is your answer

Answer 2

$z^{2}$+4xy-$4y^{2}$+$x^{2}$

[$z^{2}$-($x^{2}$-2x(2y)+$4y^{2}$)

$z^{2}$-(x-2y)2

= (z+x-2y)(z-x+2y)