5B:
a: \(\dfrac{3}{16}\cdot\dfrac{-2}{7}+\dfrac{6}{32}\cdot\dfrac{-12}{7}\)
\(=\dfrac{3}{16}\cdot\dfrac{-2}{7}+\dfrac{3}{16}\cdot\dfrac{-12}{7}\)
\(=\dfrac{3}{16}\left(-\dfrac{2}{7}-\dfrac{12}{7}\right)\)
\(=\dfrac{3}{16}\cdot\left(-2\right)=-\dfrac{3}{8}\)
b: \(\dfrac{7}{8}:\left(\dfrac{-5}{6}+\dfrac{1}{9}\right)+\dfrac{7}{8}:\left(3+\dfrac{-2}{5}\right)\)
\(=\dfrac{7}{8}:\dfrac{-15+2}{18}+\dfrac{7}{8}:\dfrac{-13}{5}\)
\(=\dfrac{7}{8}\cdot\dfrac{-18}{13}+\dfrac{7}{8}\cdot\dfrac{-5}{13}\)
\(=\dfrac{7\cdot\left(-23\right)}{104}=\dfrac{-161}{104}\)
c: \(\dfrac{8}{5}\cdot\dfrac{45}{17}\cdot\left(-\dfrac{25}{16}\right)\cdot\left(-\dfrac{34}{9}\right)\)
\(=\dfrac{8}{5}\cdot\dfrac{45}{17}\cdot\dfrac{25}{16}\cdot\dfrac{34}{9}\)
\(=\dfrac{8}{16}\cdot\dfrac{25}{5}\cdot\dfrac{45}{9}\cdot\dfrac{34}{17}\)
\(=\dfrac{1}{2}\cdot5\cdot5\cdot2=25\)
5A:
a: \(\dfrac{1}{7}\cdot\dfrac{3}{-16}+\dfrac{1}{7}\cdot\dfrac{-13}{16}\)
\(=\dfrac{1}{7}\left(-\dfrac{3}{16}-\dfrac{13}{16}\right)\)
\(=\dfrac{1}{7}\cdot\dfrac{-16}{16}=-\dfrac{1}{7}\)
b: \(\left(-\dfrac{3}{5}+\dfrac{5}{6}\right):\dfrac{4}{7}+\left(\dfrac{1}{6}+\dfrac{2}{-5}\right):\dfrac{4}{7}\)
\(=\left(-\dfrac{3}{5}+\dfrac{5}{6}+\dfrac{1}{6}+\dfrac{-2}{5}\right):\dfrac{4}{7}\)
\(=\left(1-1\right):\dfrac{4}{7}=0:\dfrac{4}{7}=0\)
c: \(\dfrac{3}{7}\cdot\dfrac{3}{26}-\dfrac{1}{14}\cdot\dfrac{-4}{13}\)
\(=\dfrac{9}{182}+\dfrac{4}{182}=\dfrac{13}{182}=\dfrac{1}{14}\)
d: \(\left(-0,25\right)\cdot1\dfrac{1}{5}\cdot\dfrac{-5}{16}\cdot\left(2\dfrac{2}{7}\right)\)
\(=\dfrac{-1}{4}\cdot\dfrac{6}{5}\cdot\dfrac{-5}{16}\cdot\dfrac{16}{7}\)
\(=\dfrac{1}{4}\cdot\dfrac{6}{5}\cdot\dfrac{5}{7}\)
\(=\dfrac{1}{4}\cdot\dfrac{6}{7}=\dfrac{6}{28}=\dfrac{3}{14}\)
