Tính
a) \(\frac{-3}{4}. \frac{12}{-5}. (\frac{-25}{6})\)
b) \((-2). \frac{-38}{21} .\frac{-7}{4} . (-\frac{3}{8})\)
c) \((\frac{11}{12}: \frac{33}{16}).\frac{3}{5}\)
d) \(\frac{7}{23} . \left [ (-\frac{8}{6}) - \frac{45}{18} \right ]\)
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a) \(\frac{-3}{4}. \frac{12}{-5}. (\frac{-25}{6})\) = \(\frac{-3}{4}. \frac{-12}{5} . \frac{-25}{6} = \frac{-3.(-12).(-25)}{4.5.6} = \frac{-3.5}{2} = -\frac{15}{2}\)
b) \((-2). \frac{-38}{21} .\frac{-7}{4} . (-\frac{3}{8})\) = \(\frac{(-2)(-38)(-7)(-3)}{21.4.8} = \frac{38}{2.8} = \frac{19}{8} = 2\frac{3}{8}\)
c) \((\frac{11}{12}: \frac{33}{16}).\frac{3}{5}\) = \((\frac{11}{12}.\frac{16}{33}).\frac{3}{5} = (\frac{4}{3.5}). \frac{3}{5} = \frac{4.3}{3.3.5} = \frac{4}{15}\)
d) \(\frac{7}{23} . \left [ (-\frac{8}{6}) - \frac{45}{18}\ \right ]\) = \(\frac{7}{23}.(\frac{-8}{6}- \frac{15}{6}) = \frac{-7}{6} = -1\frac{1}{6}\)