Thực hiện phép tính h) 0 , 8 : { 0 , 2 − 7 [ 1/ 6 + ( 5/ 21 − 5 /14 ) ] } ;

h) \(0,8:\left\{ {0,2 - 7\left[ {\frac{1}{6} + \left( {\frac{5}{{21}} - \frac{5}{{14}}} \right)} \right]} \right\}\)

\( = 0,8:\left\{ {0,2 - 7\left[ {\frac{1}{6} + \left( { - \frac{5}{{42}}} \right)} \right]} \right\}\)

\[ = 0,8:\left\{ {0,2 - 7\left[ {\frac{1}{{21}}} \right]} \right\}\]

\[ = \frac{4}{5}:\left\{ {\frac{1}{5} - \frac{1}{3}} \right\}\]

\[ = \frac{4}{5}:\left\{ {\frac{{ - 2}}{{15}}} \right\}\]\[ = - 6\].