Решение:
- \(\frac{34}{63} \cdot \frac{14}{17} = \frac{2\cdot 17}{9\cdot 7} \cdot \frac{2\cdot 7}{17} = \frac{2}{9} \cdot \frac{2}{1} = \frac{4}{9}\)
- \(7\frac{3}{15} \cdot 10 = \frac{7\cdot 15+3}{15} \cdot 10 = \frac{105+3}{15} \cdot 10 = \frac{108}{15} \cdot 10 = \frac{108}{3} \cdot 2 = 36 \cdot 2 = 72\)
- \(7\frac{3}{14} \cdot 0 = 0\)
- \(\left(-\frac{7}{8}\right)^2 = \frac{\left(-7\right)^2}{8^2} = \frac{49}{64}\)
Ответ: a) \(\frac{4}{9}\), b) \(72\), c) \(0\), d) \(\frac{49}{64}\).