\[- 3\frac{5^{\backslash 4}}{6} - 2\frac{3^{\backslash 3}}{8} =\]
\[= - \left( 3\frac{20}{24} + 2\frac{9}{24} \right) =\]
\[= - 5\frac{29}{24} = - 6\frac{5}{24}.\]