Answer
$(y-4)(y^2+4y+16)$
Work Step by Step
RECALL:
$A^3-B^3=(A-B)(A^2+AB+B^2)$
The given binomial can be written as:
$y^3-4^3$
The binomial above is a difference of two cubes.
Factor using the the formula above with $A=y$ and $B=4$ to obtain:
$=(y-4)(y^2+y(4) + 4^2)
\\=(y-4)(y^2+4y+16)$
