I would apprieciate any and all feedback regarding the following problem. Thank you soooo much! :)

1. The expression x^4 + x^2 +1 cannot be factored using known techniques. However, by writing x^2 as 2x^2 -x^2, we obtain

x^4 + 2x^2 +1 -x^2 which can be factored using a difference of squares.

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

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

Use this technique to factor:

a) x^4 + 5x^2 + 9

b) 4x^4 + 8x^2 +9