To multiply the fractions \( \frac{5}{7} \) and \( \frac{3}{4} \), you multiply the numerators together and the denominators together:
\[ \frac{5}{7} \times \frac{3}{4} = \frac{5 \times 3}{7 \times 4} = \frac{15}{28} \]
So, \( \frac{5}{7} \times \frac{3}{4} = \frac{15}{28} \).