You might try factoring by grouping first.
Note that y^3+6y^2 = y^2(y+6), and that -4y-24 = -4(y+6). So, (y+6) is a factor common to the first group of 2 terms and the 2nd grp of 2 terms.
We get (y+6)[y^2 - 4]. Note that y^2-4 is easily factorable: (y-2)(y+2),
so we now have three factors of the original poly:
(y+6), (y-2) and (y+2) (answer)
