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 $x.$
Thx!
The polynomial factors as (x^2 + xy + y^2 + z^2)(x^2 - xy + y^2 + z^2).
Hint:
Use the difference of two squares 3 times.
Please no one expand on this.
