\[\frac{5k - 3}{k + 3} - \frac{k}{k + 4}\ :\frac{k}{k^{2} - 16} - \frac{6k}{k + 3} =\]
\[= \frac{5k - 3 - 6k}{k + 3} - \frac{k}{k + 4} \cdot \frac{k^{2} - 16}{k} =\]
\[= \frac{- k - 3}{k + 3} - \frac{(k - 4)(k + 4)}{k + 4} =\]
\[= - \frac{k + 3}{k + 3} - (k - 4) =\]
\[= - 1 - k + 4 = - k + 3.\]
\[k + 3 = 2\frac{7}{11}\]
\[k = 2\frac{7}{11} - 3 = - \frac{4}{11}.\]
\[Ответ:при\ k = - \frac{4}{11}.\]