Đáp án:
$\begin{array}{l}
1)\\
A = \dfrac{{ - 4}}{7}.\dfrac{2}{9} + \dfrac{{ - 4}}{7}.\dfrac{7}{9} + 2\dfrac{4}{7}\\
= \dfrac{{ - 4}}{7}.\left( {\dfrac{2}{9} + \dfrac{7}{9}} \right) + 2 + \dfrac{4}{7}\\
= \dfrac{{ - 4}}{7}.\dfrac{9}{9} + \dfrac{4}{7} + 2\\
= \dfrac{{ - 4}}{7} + \dfrac{4}{7} + 2\\
= 2\\
2)B = 0,5.1\dfrac{1}{3}.10.0,75.\dfrac{7}{{35}}\\
= \dfrac{1}{2}.\dfrac{4}{3}.10.\dfrac{3}{4}.\dfrac{1}{5}\\
= 1\\
3)C = - 1,7.2.3 + 1,7.\left( { - 3.7} \right) - 1,7.3 - 0,17:0,1\\
= \left( { - 1,7} \right).6 + \left( { - 1,7} \right).21 + \left( { - 1,7} \right).3 + \left( { - 1,7} \right)\\
= \left( { - 1,7} \right).\left( {6 + 21 + 3} \right) + \left( { - 1,7} \right)\\
= \left( { - 1,7} \right).30 + \left( { - 1,7} \right)\\
= - 51 - 1,7\\
= - 52,7
\end{array}$
