we know that
A difference of squares problem can be factored as follows:
[tex]a^{2}-b^{2} =(a+b)(a-b)[/tex]
in this problem we have
[tex]t^{4}-16[/tex]
Applying difference of squares
[tex]t^{4}-16=(t^{2}-4)( t^{2}+4)[/tex]
the term
[tex](t^{2}-4)=(t+2)(t-2)[/tex]
substitute
[tex](t^{2}-4)( t^{2}+4)=(t+2)(t-2)( t^{2}+4)[/tex]
therefore
the answer is
[tex](t+2)(t-2)( t^{2}+4)[/tex]
