Tính giá trị của biểu thức a) 7/ 6 × 3 /8 + 7/ 6 : 4 + 7 /6

a) \(\frac{7}{6} \times \frac{3}{8} + \frac{7}{6}:4 + \frac{7}{6}\)             

\( = \frac{7}{6} \times \frac{3}{8} + \frac{7}{6} \times \frac{1}{4} + \frac{7}{6}\)

\( = \frac{7}{6} \times \left( {\frac{3}{8} + \frac{1}{4} + 1} \right)\)

\( = \frac{7}{6} \times \left( {\frac{3}{8} + \frac{2}{8} + \frac{8}{8}} \right)\)

\( = \frac{7}{6} \times \frac{{13}}{8}\)

\( = \frac{{91}}{{48}}\)

b) \(\frac{2}{5} \times \frac{8}{7} - \frac{2}{9} \times \frac{8}{5}\)

\( = \frac{2}{5} \times \frac{8}{7} - \frac{2}{5} \times \frac{8}{9}\)

\( = \frac{2}{5} \times \left( {\frac{8}{7} - \frac{8}{9}} \right)\)

\( = \frac{2}{5} \times \left( {\frac{{72}}{{63}} - \frac{{56}}{{63}}} \right)\)

\( = \frac{2}{5} \times \frac{{16}}{{63}}\)

\( = \frac{{32}}{{315}}\)