a) $$\left(7 + \frac{5}{12}\right) \cdot 12 = 7 \cdot 12 + \frac{5}{12} \cdot 12 = 84 + 5 = 89$$
Ответ: $$89$$
б) $$9.7 \cdot \frac{4}{9} = \frac{97}{10} \cdot \frac{4}{9} = \frac{97 \cdot 4}{10 \cdot 9} = \frac{388}{90} = \frac{194}{45} = 4\frac{14}{45}$$
Ответ: $$4\frac{14}{45}$$