3) Сократите дробь: а) \(\frac{a^2b^5}{ab^7}\); б) \(\frac{-63xy^5}{81xy^4}\); в) \(\frac{30a^2c^3}{48a^3c^2}\).

1. \(\frac{a^2b^5}{ab^7}=\frac{a}{b^2}\).
2. \(\frac{-63xy^5}{81xy^4}=-\frac{7y}{9}\).
3. \(\frac{30a^2c^3}{48a^3c^2}=\frac{5c}{8a}\).

Ответ: а) \(\frac{a}{b^2}\); б) \(-\frac{7y}{9}\); в) \(\frac{5c}{8a}\).