разложить на множители x^8+x^4-2

x^8+x^4-2=

(x^4+1/2)^2-(3/2)^2=

(x^4+1/2+3/2)(x^4+1/2-3/2)=

(x^4+2)(x^4-1)=

(x^4+2)(x^2+1)(x^2-1)=

(x^4+2)(x^2+1)(x-1)(x+1)