How to factor the polynomial $x^4-x^2 + 1$ How do I factor this polynomial: $$x^4-x^2+1$$
The solution is: $$(x^2-x\sqrt{3}+1)(x^2+x\sqrt{3}+1)$$
Can you please explain what method is used there and what methods can I use generally for 4th or 5th degree polynomials?

You can get it by$$x^4-x^2+1=x^4+2x^2-2x^2-x^2+1=x^4+2x^2+1-3x^2=(x^2+1)^2-(\sqrt 3x)^2.$$
