Answer
$ (x - 4) (x+4)(x^2 +16)$
Work Step by Step
$x^4 - 256= (x^2)^2 - (16)^2 = (x^2 - 16) (x^2 +16) = ((x)^2 - 4^2)(x^2 +16) = (x - 4) (x+4)(x^2 +16)$
You can help us out by revising, improving and updating this answer.
Update this answerAfter you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.