﹙3分之2a的4次方b的7次幂-9分之1a²b的6次幂﹚÷﹙-3分之1ab³﹚²
=﹙2a的4次方b的7次幂/3-a²b的6次幂/9﹚÷﹙a²b的6次方/9﹚
=6a²b-1