28. Сократите дробь: а) \(\frac{4a^2}{6ac}\); б) \(\frac{7x^2y}{21xy^2}\); в) \(\frac{56m^2n^3}{35mn^5}\); г) \(\frac{25p^4q}{100p^2q^3}\).

1. а) \(\frac{4a^2}{6ac}=\frac{2a}{3c}\).
2. б) \(\frac{7x^2y}{21xy^2}=\frac{x}{3y}\).
3. в) \(\frac{56m^2n^3}{35mn^5}=\frac{8m}{5n^2}\).
4. г) \(\frac{25p^4q}{100p^2q^3}=\frac{p^2}{4q^2}\).

Ответ: а) \(\frac{2a}{3c}\); б) \(\frac{x}{3y}\); в) \(\frac{8m}{5n^2}\); г) \(\frac{p^2}{4q^2}\).