先算乘方,再算乘除.都化为分数指数幂.(-2a^1/3b^-3/4)(-a^1/2b^-1/3)^6÷(-3a^2/3b^-1/4)=(-2a^1/3b^-3/4)(a^3b^-2)÷(-3a^2/3b^-1/4)=(2/3)a^(1/3+3-2/3)*b^(-3/4-2+1/4)=(2/3)a^(8/3)*b^(-5/2).