Đáp án:
$\begin{array}{l}
1)\dfrac{{{4^5}{{.9}^5} - {{2.6}^{10}}}}{{{2^{10}}{{.3}^8} + {6^8}.20}} = \dfrac{{{2^{10}}{{.3}^{10}} - {{2.2}^{10}}{{.3}^{10}}}}{{{2^{10}}{{.3}^8} + {2^8}{{.3}^8}{{.2}^2}.5}}\\
= \dfrac{{{2^{10}}{{.3}^{10}}.\left( {1 - 2} \right)}}{{{2^{10}}{{.3}^8}.\left( {1 + 5} \right)}}\\
= \dfrac{{{3^2}.\left( { - 1} \right)}}{6}\\
= \dfrac{{ - 9}}{6} = - \dfrac{3}{2}\\
2)\dfrac{{{{25}^5}{{.81}^4} - {9^3}{{.15}^9}}}{{{5^{10}}{{.9}^8} + {{25}^5}{{.27}^6}}} = \dfrac{{{5^{10}}{{.3}^{16}} - {3^6}{{.3}^9}{{.5}^9}}}{{{5^{10}}{{.3}^{16}} + {5^{10}}{{.3}^{18}}}}\\
= \dfrac{{{5^9}{{.3}^{15}}.\left( {5.3 - 1} \right)}}{{{5^{10}}{{.3}^{16}}.\left( {1 + {3^2}} \right)}}\\
= \dfrac{{14}}{{5.3.10}} = \dfrac{7}{{75}}
\end{array}$
