Answer:
[tex](3x+4)(3x-4)(9x^2+16)[/tex]
Step-by-step explanation:
Given [tex]p(x)=81x^4-256[/tex]
Factor using difference of squares
[tex]p(x)=(9x^2-16)(9x^2+16)[/tex]
Note that the factor [tex](9x^2-16)[/tex] can still be factored using, again, difference of squares. Thus,
[tex]p(x)=(3x+4)(3x-4)(9x^2+16)[/tex]