记住 (a^b)^c=a^(bc) 就成了
(4a^3/3b^2)^2*(-3b/2a^2)^3*(-b/3a)^2
=[16a^6/(9b^4)]*[-27b^3/(8a^6)]*[b^2/(9a^2)
=-2b/3a^2