Question

Factorise using identities.
 x4 x2 1

Answer 1

HEY!!

 x4 + x2 + 1

= x4 + 2x2 + 1 - x2
= (x2 + 1) - x2
= (x2 + 1 - x ) (x2 +1 + x )

Answer 2

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