Các bn lm hộ mk bài này vớiii!

Đáp án:

c) -5

Giải thích các bước giải:

\(\begin{array}{l}
c)\dfrac{{21.6 - 21}}{{5 - 26}}\\
 =  - \dfrac{{21\left( {6 - 1} \right)}}{{21}} =  - 5\\
d)\dfrac{{ - 5.9}}{{12.9}} =  - \dfrac{5}{{12}}\\
e)\dfrac{{125}}{{1000}} = \dfrac{{{5^3}}}{{{5^3}.8}} = \dfrac{1}{8}\\
f)\dfrac{{103}}{{3090}} = \dfrac{{103}}{{103.30}} = \dfrac{1}{{30}}\\
g)\dfrac{{{2^3}{{.3}^4}}}{{{2^2}{{.3}^2}.5}} = \dfrac{{{{2.3}^2}}}{5} = \dfrac{{18}}{5}\\
h)\dfrac{{{2^4}{{.5}^2}{{.11}^2}.7}}{{{2^3}{{.5}^3}{{.7}^2}.11}}\\
 = \dfrac{{2.11}}{{5.7}} = \dfrac{{22}}{{35}}\\
k)\dfrac{{{3^{10}}.{{\left( { - 5} \right)}^{21}}}}{{{{\left( { - 5} \right)}^{20}}{{.3}^{12}}}} =  - \dfrac{5}{{{3^2}}} =  - \dfrac{5}{9}
\end{array}\)