\[3,4 + 1\frac{5}{7} = \frac{34}{10} + 1\frac{5}{7} =\]
\[= \frac{17^{\backslash 7}}{5} + \frac{15^{\backslash 5}}{7} = \frac{118}{35} + \frac{75}{35} =\]
\[= \frac{293}{75} = 3\frac{68}{75}.\]