488 a) \(\frac{3}{7}a\) при \(a = \frac{3}{7}\), \(a = \frac{119}{66}\), \(a = \frac{28}{33}\), \(a = 1\)

Решение: 1) Если \(a = \frac{3}{7}\), то \(\frac{3}{7} \cdot \frac{3}{7} = \frac{9}{49}\). 2) Если \(a = \frac{119}{66}\), то \(\frac{3}{7} \cdot \frac{119}{66} = \frac{3 \cdot 119}{7 \cdot 66} = \frac{357}{462}\). Сократим дробь на 21: \(\frac{357:21}{462:21} = \frac{17}{22}\). 3) Если \(a = \frac{28}{33}\), то \(\frac{3}{7} \cdot \frac{28}{33} = \frac{3 \cdot 28}{7 \cdot 33} = \frac{84}{231}\). Сократим дробь на 21: \(\frac{84:21}{231:21} = \frac{4}{11}\). 4) Если \(a = 1\), то \(\frac{3}{7} \cdot 1 = \frac{3}{7}\). Ответ: \(\frac{9}{49}\), \(\frac{17}{22}\), \(\frac{4}{11}\), \(\frac{3}{7}\).