Đáp án:
77) \( - \dfrac{{95}}{{24}}\)
Giải thích các bước giải:
\(\begin{array}{l}
76)\\
P = \dfrac{{13}}{{30}} + \dfrac{{28}}{{45}}.\dfrac{5}{2}.\dfrac{{\dfrac{5}{6}}}{{\dfrac{{53}}{{90}}}}.\dfrac{{53}}{{50}}\\
= \dfrac{{13}}{{30}} + \dfrac{{28}}{{45}}.\dfrac{5}{2}.\dfrac{{75}}{{53}}.\dfrac{{53}}{{50}}\\
= \dfrac{{13}}{{30}} + \dfrac{7}{3} = \dfrac{{83}}{{30}}\\
77)Q = \dfrac{{\left( {\dfrac{{676}}{{25}}:\dfrac{{13}}{5} + \dfrac{{81}}{{10}} - \dfrac{{169}}{4}} \right):\dfrac{1}{{40}}}}{{{{\left( {\dfrac{{7524}}{{125}}:\dfrac{{12}}{5} - \dfrac{{27}}{{25}}} \right)}^2} - \dfrac{6}{{25}}.1400}}\\
= \dfrac{{\left( {\dfrac{{52}}{5} + \dfrac{{81}}{{10}} - \dfrac{{169}}{4}} \right).40}}{{{{\left( {\dfrac{{627}}{{25}} - \dfrac{{27}}{{25}}} \right)}^2} - 336}}\\
= \dfrac{{ - \dfrac{{95}}{4}.40}}{{576 - 336}} = \dfrac{{ - 950}}{{240}} = - \dfrac{{95}}{{24}}
\end{array}\)
