Question

x^4-4x^3-2x^2+4X+1=0

Answer 1

(x^4-x^2)-(4x^3-4x)-(x^2-1)=0
x^2(x^2-1)-4x(x^2-1)-(x^2-1)=0
(x^2-1)*(x^2-4x-1)=0
x^2-1=0
x=1, x=-1
x^2-4x-1=0
x=2+sgrt5,  x=2-sgrt5

Answer 2

Решение во вложении.