Đáp án:
$\begin{array}{l}
A = 23\dfrac{1}{3}:\left( {\dfrac{{ - 5}}{7}} \right) - 13\dfrac{1}{3}:\left( { - \dfrac{5}{7}} \right)\\
= \left( {23\dfrac{1}{3} - 13\dfrac{1}{3}} \right):\left( { - \dfrac{5}{7}} \right)\\
= \left( {23 + \dfrac{1}{3} - 13 - \dfrac{1}{3}} \right).\dfrac{{ - 7}}{5}\\
= 10.\dfrac{{ - 7}}{5}\\
= - 14\\
B = \dfrac{{{{\left( {\dfrac{4}{9}} \right)}^2}.\left( { - \dfrac{9}{{16}}} \right).{{\left( { - 1} \right)}^{19}}}}{{{{\left( {\dfrac{4}{{25}}} \right)}^2}.{{\left( {\dfrac{{ - 25}}{{144}}} \right)}^2}.{{\left( {\dfrac{{ - 36}}{{144}}} \right)}^2}}}\\
= \dfrac{{\dfrac{{16}}{{81}}.\dfrac{{ - 9}}{{16}}.\left( { - 1} \right)}}{{\dfrac{{16}}{{{{25}^2}}}.\dfrac{{{{25}^2}}}{{{{144}^2}}}.\dfrac{{{{36}^2}}}{{{{144}^2}}}}}\\
= \dfrac{{\dfrac{1}{9}}}{{\dfrac{1}{{20736}}}} = 2304
\end{array}$
