a) \(\frac{-5}{8}\cdot\left(\frac{4}{9}+\frac{-7}{12}\right)\)
\(=\frac{-5}{8}\cdot\frac{-5}{36}\)
\(=\frac{25}{288}\)
b) \(\left(-3,2\right)\cdot\frac{-15}{64}+\left(0,8-2\frac{4}{5}\right):3\frac{1}{2}\)
\(=\frac{3}{4}+\left(-2\right):\frac{7}{2}\)
\(=\frac{3}{4}+\frac{-4}{7}\)
\(=\frac{5}{28}\)
=))