(3a^-2b^-4)²·(2a³b³)²/(3^-1a²b³）^-3
=9a^(-4)·b^(-8)·4a^6·b^6/(27a^-6·b^-9)
=(4/3)·a²b^(-2)·a^6·b^9
=(4/3)·a^8·b^7