Question 398877
given:
x^6-9x^4-x^2+9=0 
.
group terms:
(x^6-9x^4)-(x^2-9)=0 
x^4(x^2-9)-(x^2-9)=0 
(x^2-9)(x^4-1)=0 
But, both of the terms are "difference of squares" so:
(x-3)(x+3)(x^2-1)(x^2+1)
One more:
(x-3)(x+3)(x-1)(x+1)(x^2+1)