Сократите дробь: а) \(\frac{y^2-16}{3y+12}\); б) \(\frac{5x-15y}{x^2-9y^2}\); в) \(\frac{(c+2)^2}{7c^2+14c}\); д) \(\frac{a^2+10a+25}{a^2-25}\); е) \(\frac{y^2-9}{y^2-6y+9}\).

1. \(\frac{y^2-16}{3y+12}=\frac{(y-4)(y+4)}{3(y+4)}=\frac{y-4}{3}\).
2. \(\frac{5x-15y}{x^2-9y^2}=\frac{5(x-3y)}{(x-3y)(x+3y)}=\frac{5}{x+3y}\).
3. \(\frac{(c+2)^2}{7c^2+14c}=\frac{(c+2)^2}{7c(c+2)}=\frac{c+2}{7c}\).
4. \(\frac{a^2+10a+25}{a^2-25}=\frac{(a+5)^2}{(a-5)(a+5)}=\frac{a+5}{a-5}\).
5. \(\frac{y^2-9}{y^2-6y+9}=\frac{(y-3)(y+3)}{(y-3)^2}=\frac{y+3}{y-3}\).

Ответ: а) \(\frac{y-4}{3}\); б) \(\frac{5}{x+3y}\); в) \(\frac{c+2}{7c}\); д) \(\frac{a+5}{a-5}\); е) \(\frac{y+3}{y-3}\).