Question

(x+y)²+(z-w)²-(y-z)-(w-x)+2(x-z)(y-w)

Answer 1

$x^2+2xy+y^2+z^2-2zw+w^2 -y+z+2[xy-wy-zy+zw}$

$x^2+2xy+y^2+z^2-2zw+w^2-y+z+2xy-2wy-2zy+2zw$