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Tính $1,2 \times \left(\frac{15}{4} - 5\frac{3}{4}\right) + \frac{16}{7} \times \left(\frac{85}{8} - \frac{21}{8}\right)$

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Biết Tuốt
$\begin{array}{l} 1,2\left( {\dfrac{{15}}{4} - 5\dfrac{3}{4}} \right) + \dfrac{{16}}{7}\left( {\dfrac{{85}}{8} - \dfrac{{21}}{8}} \right) = 1,2\left( {\dfrac{{15}}{4} - \dfrac{{23}}{4}} \right) + \dfrac{{16}}{7}\left( {\dfrac{{85}}{8} - \dfrac{{21}}{8}} \right)\\ = 1,2.\dfrac{{15 - 23}}{4} + \dfrac{{16}}{7}.\dfrac{{85 - 21}}{8}\\ = 1,2.\dfrac{{ - 8}}{4} + \dfrac{{16}}{7}.\dfrac{{64}}{8} = 1,2.2 + \dfrac{{16}}{7}.8\\ = \dfrac{{12}}{{10}}.\left( { - 2} \right) + \dfrac{{16}}{7}.8 = - \dfrac{{12}}{5} + \dfrac{{128}}{7} = \dfrac{{556}}{{35}} \end{array}$
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