5.519 Вычислите произведение: а) 63 57. б) 347 в) 42 5 47

Ответ: а) 1, б) 347, в) \(\frac{5}{47}\)

а) \(\frac{63}{95}\) \(\cdot\) \(\frac{5}{7}\) \(\cdot\) \(\frac{7}{5}\) = \(\frac{63 \cdot 5 \cdot 7}{95 \cdot 7 \cdot 5}\) = \(\frac{63}{95}\) = 1

б) 347 \(\cdot\) \(\frac{9}{11}\) \(\cdot\) \(\frac{11}{9}\) = 347 \(\cdot\) \(\frac{9 \cdot 11}{11 \cdot 9}\) = 347 \(\cdot\) 1 = 347

в) \(\frac{42}{47}\) \(\cdot\) \(\frac{5}{431}\) \(\cdot\) \(\frac{47}{42}\) = \(\frac{42 \cdot 5 \cdot 47}{47 \cdot 431 \cdot 42}\) = \(\frac{5}{431}\)

Ответ: а) 1, б) 347, в) \(\frac{5}{431}\)