Вариант №2. 1. Сократите дробь: 1) \(\frac{36a^{12}b^7}{54a^8b^{11}}\); 2) \(\frac{18mn-27m}{9mn}\); 3) \(\frac{3c+15}{c^2-25}\); 4) \(\frac{x^2-14x+49}{49-x^2}\).

1. \(\frac{36a^{12}b^7}{54a^8b^{11}}=\frac{2a^4}{3b^4}\).
2. \(\frac{18mn-27m}{9mn}=\frac{9m(2n-3)}{9mn}=\frac{2n-3}{n}\).
3. \(\frac{3c+15}{c^2-25}=\frac{3(c+5)}{(c-5)(c+5)}=\frac{3}{c-5}\).
4. \(\frac{x^2-14x+49}{49-x^2}=\frac{(x-7)^2}{(7-x)(7+x)}=\frac{7-x}{x+7}\).

Ответ: 1) \(\frac{2a^4}{3b^4}\); 2) \(\frac{2n-3}{n}\); 3) \(\frac{3}{c-5}\); 4) \(\frac{7-x}{x+7}\).