how would you factor -x^4 + 8x^2 + 9?

-x^4 + 8x^2 + 9
= -(x^4 - 8x^2 - 9)
= -(x^4 + x^2 - 9x^2 - 9)
= -[(x^4 + x^2) - (9x^2 + 9)]
= -[x^2(x^2 + 1) - 9(x^2 + 1)]
= -(x^2 + 1)(x^2 - 9)
= -(x^2 + 1)(x^2 - 3^2)
= -(x^2 + 1)(x + 3)(x - 3)

x^4-8x^2-9
(x^2-9)(x^2+1)
(x+3)(x-3)(x^2+1)

(-x^2 - 1)(x^2 - 9)

i think is right... I'm sorta tired and did this quickly without thinking so u might wanna double check... oh and i think it can be simplified more...
(x^2 - 9) can go to (x - 3)(x + 3)
and i don't think (-x^2 - 1) can be simplified more, but maybe it can... u can use the quadratic formula to check.

(1+x^2)(9-x^2)=(1+x^2)(3-x)(3+x)
God bless you.