Ответ:

Преобразуем смешанные числа:

\(-5\frac{1}{16}=-\frac{81}{16}\), \(1\frac{1}{8}=\frac{9}{8}=\frac{18}{16}\).

\(-\frac{81}{16}+\frac{18}{16}=-\frac{63}{16}\).

\(-\frac{5}{6}-\frac{3}{4}=-\frac{10}{12}-\frac{9}{12}=-\frac{19}{12}\).

\(\left(-\frac{63}{16}\right)\left(-\frac{19}{12}\right)=\frac{63\cdot19}{16\cdot12}=\frac{399}{64}=6\frac{15}{64}\).

Ответ: \(\frac{399}{64}=6\frac{15}{64}\).