Решение:
а)
- \( 7\frac{2}{9} = \frac{7 \cdot 9 + 2}{9} = \frac{63+2}{9} = \frac{65}{9} \)
- \( 5\frac{8}{17} = \frac{5 \cdot 17 + 8}{17} = \frac{85+8}{17} = \frac{93}{17} \)
б)
- \( 12\frac{17}{48} = 11 + 1 + \frac{17}{48} = 11 + \frac{48}{48} + \frac{17}{48} = 11\frac{65}{48} \)
в)
- \( 4 = \frac{4 \cdot 13}{13} = \frac{52}{13} \)
- \( 17 = \frac{17 \cdot 13}{13} = \frac{221}{13} \)
Ответ: а) \( \frac{65}{9}; \frac{93}{17} \); б) \( 11\frac{65}{48} \); в) \( \frac{52}{13}; \frac{221}{13} \).