5 4.28 27/3 5 26 14 1 17 Q 8 2行 ح 2- 12 19 2 17°34 10 3 // 7 0 5 ff 2 23 17 2

Решение:

1. $$\frac{2}{5} \cdot \frac{28}{26} = \frac{2 \cdot 28}{5 \cdot 26} = \frac{2 \cdot 2 \cdot 14}{5 \cdot 2 \cdot 13} = \frac{28}{65}$$
2. $$\frac{14}{17} \cdot \frac{1}{8} = \frac{14 \cdot 1}{17 \cdot 8} = \frac{7 \cdot 2 \cdot 1}{17 \cdot 4 \cdot 2} = \frac{7}{68}$$
3. $$\frac{12}{17} \cdot \frac{19}{34} = \frac{12 \cdot 19}{17 \cdot 34} = \frac{12 \cdot 19}{17 \cdot 2 \cdot 17} = \frac{228}{578} = \frac{114}{289}$$
4. $$\frac{10}{11} \cdot \frac{3}{5} = \frac{10 \cdot 3}{11 \cdot 5} = \frac{2 \cdot 5 \cdot 3}{11 \cdot 5} = \frac{6}{11}$$
5. $$\frac{7}{23} \cdot \frac{11}{17} = \frac{7 \cdot 11}{23 \cdot 17} = \frac{77}{391}$$

Ответ:

1. $$\frac{28}{65}$$
2. $$\frac{7}{68}$$
3. $$\frac{114}{289}$$
4. $$\frac{6}{11}$$
5. $$\frac{77}{391}$$