n^4 - 12n^2+16=n^4-8n^2+16-4n^2=(n^2-4)^2-4n^2=(n^2-4-2n)(n^2-4+2)
у^8-у^6-4y^2-16=(y^8-16)-y^2(y^4+4)=(y^4-4)(y^4+4)-y^2(y^4+4)=(y^4+4)(y^4-4-y^2)=
(y^4+4y^2+4-4y^2)(y^4-4-y^2)=((y^2+2)-4y^2)(y^4-4-y^2)=(y^2-2y+2)(y^2+2y+2)(y^4-4-y^2)
n^4 - 12n^2+16=n^4-8n^2+16-4n^2=(n^2-4)^2-4n^2=(n^2-4-2n)(n^2-4+2)
у^8-у^6-4y^2-16=(y^8-16)-y^2(y^4+4)=(y^4-4)(y^4+4)-y^2(y^4+4)=(y^4+4)(y^4-4-y^2)=
(y^4+4y^2+4-4y^2)(y^4-4-y^2)=((y^2+2)-4y^2)(y^4-4-y^2)=(y^2-2y+2)(y^2+2y+2)(y^4-4-y^2)