1. Выполните действия: 1) \(\frac{5b}{28}+\frac{9b}{28}\); 2) \(\frac{9m}{7n}-\frac{2m}{7n}\); 3) \(\frac{5x-3y}{8z}+\frac{3x-13y}{8z}\); 4) \(\frac{4c-3d}{cd}-\frac{c-3d}{cd}\); 5) \(\frac{6x}{x^2-16}-\frac{24}{x^2-16}\); 6) \(\frac{m^2+10m}{9-m^2}-\frac{4m-9}{9-m^2}\).

1. \(\frac{5b+9b}{28}=\frac{14b}{28}=\frac b2\).
2. \(\frac{9m-2m}{7n}=\frac{7m}{7n}=\frac mn\).
3. \(\frac{5x-3y+3x-13y}{8z}=\frac{8x-16y}{8z}=\frac{x-2y}{z}\).
4. \(\frac{4c-3d-c+3d}{cd}=\frac{3c}{cd}=\frac3d\).
5. \(\frac{6x-24}{x^2-16}=\frac{6(x-4)}{(x-4)(x+4)}=\frac6{x+4}\).
6. \(\frac{m^2+10m-4m+9}{9-m^2}=\frac{(m+3)^2}{(3-m)(3+m)}=\frac{m+3}{3-m}\).

Ответ: 1) \(\frac b2\); 2) \(\frac mn\); 3) \(\frac{x-2y}{z}\); 4) \(\frac3d\); 5) \(\frac6{x+4}\); 6) \(\frac{m+3}{3-m}\).