(a^2-3b^2)(a+3b)-3ab(a-b)=a³-3ab²+3a²b-9b³-3a²b+3ab²=a³-9b³∵a=(-2)^-1,b=-3^-1∴a=-1/2,b=-1/3∴原式=(-1/2)³-9(-1/3)³=-1/8+9*1/27=-1/8+1/3=(8-3)/24=5/2...