Factor \((x^2+y^2-z^2)^2-4x^2y^2\) as the product of four polynomials of degree 1, each of which has a positive coefficient of x

Mmm

\((x^2+y^2-z^2)^2-4x^2y^2\\ [(x^2+y^2-z^2)-2xy][(x^2+y^2-z^2)+2xy]\\ [(x^2+y^2-2xy)-z^2][(x^2+y^2+2xy)-z^2]\\ [(x-y)^2-z^2][(x+y)^2-z^2]\\ [((x-y)-z)((x-y)+z)][((x+y)-z)((x+y)+z)]\\ [(x-y-z)(x-y+z)][(x+y-z)(x+y+z)]\\ (x-y-z)(x-y+z)(x+y-z)(x+y+z)\\ \)