Answer
$(x^{2}+5)(7x^{2}-1)$
Work Step by Step
$7x^{4}+34x^{2}-5$
... Searching for two factors of $ac=-35$ whose sum is $b=34,$
we find$\qquad 35$ and $-1.$
Rewrite the middle term and factor in pairs:
$=7x^{4}+35x^{2}-x^{2}-5=$
$=7x^{2}(x^{2}+5)-(x^{2}+5)$
=$(x^{2}+5)(7x^{2}-1)$
