I am 4 days on it and i can't solve it. Please, any suggestions? I checked some calculators on line. but I don't have the solution yet:
Factorize:
x^4-2x^3-9x^2-3x-1
For an analytic solution of this quartic:
Solve[x^4 - 2 x^3 - 9 x^2 - 3 x - 1 == 0, x, Quartics -> True]
or for a numerical version
N[Solve[x^4 - 2 x^3 - 9 x^2 - 3 x - 1 == 0, x]]