令a=x^4+1
原式=(a-4*x^2)(a+3*x^2)+10*x^4
=a^2+a*x^2-2*x^4
=(a-2*x^2)(a+x^2)
将a=x^4+1代入,得
原式=(x^4-2*x^2+1)(x^4+x^2+1)=(x^2-1)^2*(x^4+x^2+1)