## Intermediate Algebra (6th Edition)

$(y^2+4)(y+2)(y-2)$
Using $a^2-b^2=(a+b)(a-b)$ or the factoring of the difference of two squares, then, \begin{array}{l} y^4-16 \\= (y^2+4)(y^2-4) \\= (y^2+4)(y+2)(y-2) .\end{array}