Đáp án:
\(\begin{array}{l}
a)A = \dfrac{1}{4}\\
b)B = \dfrac{1}{2}
\end{array}\)
Giải thích các bước giải:
\(\begin{array}{l}
a)A = \dfrac{{{2^8}{{.3}^{2.2}}}}{{{2^4}{{.3}^4}{{.2}^{3.2}}}} = \dfrac{{{2^8}{{.3}^4}}}{{{2^{10}}{{.3}^4}}} = \dfrac{1}{{{2^2}}} = \dfrac{1}{4}\\
b)B = \dfrac{{{2^{19}}{{.3}^{3.3}} + {{3.5.2}^{2.9}}{{.3}^{2.4}}}}{{{2^9}{{.3}^9}{{.2}^{10}} + {2^{2.10}}{{.3}^{10}}}}\\
= \dfrac{{{2^{19}}{{.3}^9} + {2^{18}}{{.3}^9}.5}}{{{2^{19}}{{.3}^9} + {2^{20}}{{.3}^{10}}}}\\
= \dfrac{{{2^{18}}{{.3}^9}\left( {2 + 5} \right)}}{{{2^{19}}{{.3}^9}\left( {1 + 2.3} \right)}}\\
= \dfrac{7}{{2.7}} = \dfrac{1}{2}
\end{array}\)
