How to factorized this 4th degree polynomial? I need your help to this polynomial's factorization.
Factorize this polynomials which doesn't have roots in Q. 
$ \ f(x) = x^4 +2x^3-8x^2-6x-1 $ 
P.S.) Are there any generalized method finding 4th degree polynomials factor?

Just working through the hint in the accepted answer, and verified with the Wolfram result in the second answer. Just for me, and maybe a check/guide for someone else:

!$x^4+2x^3+x^2−9x^2−6x−1 \\
(x^2+x)^2  - (3x+1)^2 \\
\\
((x^2+x) + (3x+1)) ((x^2+x)  - (3x+1)) \\
(x^2+4x+1) (x^2-2x-1) \\
\\
\text{quadratic formula for } (x^2+4x+1)\\
-4/2\pm\sqrt{16-4}/2 \\
-2 \pm\sqrt3 \\
\\
\text{quadratic formula for } (x^2-2x-1) \\
--2/2\pm\sqrt{4-4(-1)}/2 \\
1\pm\sqrt{4+4}/2 \\
1\pm\sqrt2 \\
\\
\text{factored form }\\
(x+2+\sqrt3)(x+2-\sqrt3)(x-1+\sqrt2)(x-1-\sqrt2)\\
$

