ж) \( 15 \cdot \frac{3}{8} \cdot \frac{4}{6} - \frac{4}{6} \cdot 15 \cdot \frac{5}{8} \)

\( 15 \cdot \frac{3}{8} \cdot \frac{4}{6} - \frac{4}{6} \cdot 15 \cdot \frac{5}{8} = 15 \cdot \frac{4}{6} \cdot (\frac{3}{8} - \frac{5}{8}) = 15 \cdot \frac{4}{6} \cdot -\frac{2}{8} = 15 \cdot \frac{4 \cdot -2}{6 \cdot 8} = 15 \cdot \frac{-8}{48} = 15 \cdot -\frac{1}{6} = -2.5 \)