3a³b³-1/2a²b十b-(4a³b³-1/4a²b-b²)十(a³b³十1/4a²b-2b²)
=3a³b³-1/2a²b+b-4a³b³+1/4a²b+b²+a³b³+1/4a²b-2b²
=b-b²
=2-(-2)²
=-2
-------------------------------------------------------------------
3a³b³-1/2a²b十b²-(4a³b³-1/4a²b-b²)十(a³b³十1/4a²b-2b²)
=3a³b³-1/2a²b+b²-4a³b³+1/4a²b+b²+a³b³+1/4a²b-2b²
=0
=2-(-2)²
=-2