3a的3次方×b的3次方减二分之一×a的二次方×b+b—（4a的三次方×b的三次方减四）=3a³b³-1/2a²b+b-4a³b³+4=-a³b³-1/2a²b+b+4=-2³×(-2)³-1/2×2²×(-2)+(-2...