(4分之3a的4次b的7次+2分之1a³次b的8次-9分之1a²b的6次)除于(-3分之1ab³),其中a=2分之1,b=-4=(9/4a^4b^7+1/2a³b^8-1/9a²b^6)÷(-1/3ab³)=-9/4a³b⁴-3/2a²b^5+1/3ab³=-ab²(9/4a²b²+3/2ab³-1/3b)=-1/2×(-4)²×[9/4×(1/2)²×(-4)²+3/2×1/2×(-4)³-1/3×(-4)]=-8×(9-48+4/3)=-8×(-113/3)=904/3