\[\frac{5x + 35}{3x - 1}\ :\frac{x^{2} - 49}{6x - 2} =\]
\[= \frac{5(x + 7) \cdot 2(3x - 1)}{(3x - 1)(x - 7)(x + 7)} =\]
\[= \frac{10}{x - 7}.\]