8. \( a - 3 \frac{7}{9} = \frac{4}{15} \)

\( a = 3 \frac{7}{9} + \frac{4}{15} = \frac{34}{9} + \frac{4}{15} = \frac{170}{45} + \frac{12}{45} = \frac{182}{45} = \frac{91}{45} \)