3y^3+12y^2-27y-108\y^2-16

(3у³ +12у²) - (27у+108)       3у²(у+4)  -27(у+4)     (у+4)(3у²-27)

=________________=__________________=_____________=

у²-16                               у²-16                             (у-4)(у+4)

     3у²-27

=_______

    у -4