a) \(\frac{3}{4}\)+ \(\frac{4}{3}\):\(\frac{2}{7}\)- \(\frac{4}{3}\)
=\(\frac{3}{4}\) +\(\frac{4}{3}\) .\(\frac{7}{2}\) -\(\frac{4}{3}\)
=\(\frac{3}{4}\) + \(\frac{14}{3}\) -\(\frac{4}{3}\)
=\(\frac{9}{12}\) +\(\frac{56}{12}\)
=\(\frac{56}{12}\) - \(\frac{4}{3}\)
=\(\frac{56}{12}\)- \(\frac{16}{12}\)
=\(\frac{10}{3}\)
b) \(\frac{5}{2}\) - [\(\frac{1}{2}\) + (\(\frac{-2}{3}\)) .\(\frac{6}{5}\)].\(\frac{2}{5}\)
= \(\frac{5}{2}\) - [\(\frac{1}{2}\) + (\(\frac{-4}{5}\))].\(\frac{2}{5}\)
= \(\frac{5}{2}\) - (\(\frac{5}{10}\) +\(\frac{-8}{10}\)).\(\frac{2}{5}\)
=\(\frac{5}{2}\)-\(\frac{3}{10}\).\(\frac{2}{5}\)
=\(\frac{5}{2}\)-\(\frac{3}{25}\)
= \(\frac{125}{50}\)-\(\frac{6}{50}\)
= \(\frac{119}{50}\)
(Mình không chắc chắn lắm!^^)
