Đáp án:
$\begin{array}{l}
A = 0,{6^3}.{a^{ - 9}}.{b^{ - 6}}.{\left( {\dfrac{{{{\left( {2b} \right)}^{ - 3}}}}{{{a^5}}}} \right)^2}\\
= \dfrac{{{3^3}}}{{{5^3}}}.\dfrac{1}{{{a^9}}}.\dfrac{1}{{{b^6}}}.\dfrac{{{{\left( {2b} \right)}^{ - 6}}}}{{{a^{10}}}}\\
= \dfrac{{27}}{{125{a^9}{b^6}}}.\dfrac{1}{{{a^{10}}{{.2}^6}.{b^6}}}\\
= \dfrac{{27}}{{125.64.{a^{19}}.{b^{12}}}}\\
= \dfrac{{27}}{{8000{a^{19}}{b^{12}}}}
\end{array}$
