Answer
$y^2(y+5)(y+6)$
Work Step by Step
For the polynomial $y^4 + 11y^3 + 30y^2=y^2(y^2 +11y +30)$, we have to find integers whose product is $30$ and whose sum is $11$. That is, we have $5$ and $6$, where $6+5=11$ and $5\times (6)=30$. Thus
$$
y^2(y^2 +11y +30)=y^2(y+5)(y+6)
.$$
