Thực hiện phép tính
a, \(\dfrac{3}{5}\)+\(\dfrac{4}{7}\). \(\dfrac{14}{6}\)
b,\(\dfrac{10}{21}\)-\(\dfrac{3}{8}\).\(\dfrac{4}{15}\)
c, (\(\dfrac{2}{3}\)+\(\dfrac{3}{4}\)).(\(\dfrac{5}{7}\)+\(\dfrac{5}{14}\))
d,\(\dfrac{4}{5}\)+\(\dfrac{3}{5}\):3-\(\dfrac{7}{8}\)