Tính
a) \(\dfrac{1}{2}\) . ( \(\dfrac{4}{3}\) + \(\dfrac{2}{5}\) ) - \(\dfrac{3}{4}\) . ( \(\dfrac{8}{9}\) + \(\dfrac{13}{3}\) )
= \(\dfrac{1}{2}\) . \(\dfrac{8}{15}\) - \(\dfrac{3}{4}\) . \(\dfrac{47}{9}\)
= \(\dfrac{4}{15}\) - \(\dfrac{47}{12}\)
= \(\dfrac{-73}{20}\)
b) \(\dfrac{1}{5}\) : \(\dfrac{1}{10}\) - \(\dfrac{1}{3}\) . ( \(\dfrac{6}{5}\)-\(\dfrac{9}{4}\) )
= 2 - \(\dfrac{1}{3}\) . \(\dfrac{-21}{20}\)
= 2 - \(\dfrac{-7}{20}\)
= \(\dfrac{47}{20}\)
c) \(\dfrac{-3}{4}\) . ( \(\dfrac{20}{9}\) - \(\dfrac{8}{15}\) ) - \(\dfrac{5}{3}\) . \(\dfrac{9}{10}\)
= \(\dfrac{-3}{4}\) . \(\dfrac{76}{45}\) - \(\dfrac{3}{2}\)
= \(\dfrac{-19}{15}\) - \(\dfrac{3}{2}\)
= \(\dfrac{-7}{30}\)
