Question

X4 + 6x2 − 7 factored?

Answer 1

$x^4 + 6x^2 - 7\\\\=(x^2-1)(x^2+7)\\\\=(x+1)(x-1)(x^2+7)\\\\=\boxed{\bf{(x+1)(x-1)(x-i \sqrt{7})(x+i \sqrt{7} )}}$

Answer 2

$x^4+6x^2-7 \\ \\ (x^2 - 1)(x^2 + 7) \ / \ factor \\ \\ (x^2 - 1^2)(x^2 + 7) \ / \ rewrite \\ \\ (x + 1)(x - 1)(x^2 + 7) \ / \ difference \ of \ squares \\ \\ Answer: (x + 1)(x - 1)(x^2 + 7)$