№2. Сократите дробь: 1) 2k(b+2)/(z(b+2)); 2) 3a²(x−1)/(3a²); 3) 25m/(5(m+b)); 4) 5(c−3)/(c−3)²; 5) 7(a+n)/(21(a+n)); 6) 3z(b+3)⁴/(b+3)⁵.

Сокращаем одинаковые множители в числителе и знаменателе.

1. \(\dfrac{2k(b+2)}{z(b+2)}=\dfrac{2k}{z}\).
2. \(\dfrac{3a^2(x-1)}{3a^2}=x-1\).
3. \(\dfrac{25m}{5(m+b)}=\dfrac{5m}{m+b}\).
4. \(\dfrac{5(c-3)}{(c-3)^2}=\dfrac{5}{c-3}\).
5. \(\dfrac{7(a+n)}{21(a+n)}=\dfrac{1}{3}\).
6. \(\dfrac{3z(b+3)^4}{(b+3)^5}=\dfrac{3z}{b+3}\).

Ответ: 1) \(\dfrac{2k}{z}\); 2) \(x-1\); 3) \(\dfrac{5m}{m+b}\); 4) \(\dfrac{5}{c-3}\); 5) \(\dfrac{1}{3}\); 6) \(\dfrac{3z}{b+3}\).