В. Сократите дробь. а) (5·4 + 7)/14; б) (156 − 39)/390; в) (72 + 48)/720; г) (52 − 12)/12; д) (639 + 207)/639; е) (11·25 − 7·25)/(25·44 − 25·14); ж) (37·8)/(37·16 + 37·4); з) (9·4 + 6·4)/(8·81 − 8·56); и) (12·5 − 12·3)/(12·4); к) (2·24 + 5·6)/(25·64 − 25·4); л) (64·8 + 64·10)/(32·24 + 32·48); м) (61·2 + 61·30)/(61 + 61·3).

Вынесем общие множители в числителе и знаменателе и сократим дроби.

1. а) \(\dfrac{5\cdot4+7}{14}=\dfrac{27}{14}\).
2. б) \(\dfrac{156-39}{390}=\dfrac{117}{390}=\dfrac{3}{10}\).
3. в) \(\dfrac{72+48}{720}=\dfrac{120}{720}=\dfrac{1}{6}\).
4. г) \(\dfrac{52-12}{12}=\dfrac{40}{12}=\dfrac{10}{3}\).
5. д) \(\dfrac{639+207}{639}=\dfrac{846}{639}=\dfrac{94}{71}\).
6. е) \(\dfrac{11\cdot25-7\cdot25}{25\cdot44-25\cdot14}=\dfrac{25(11-7)}{25(44-14)}=\dfrac{4}{30}=\dfrac{2}{15}\).
7. ж) \(\dfrac{37\cdot8}{37\cdot16+37\cdot4}=\dfrac{37\cdot8}{37(16+4)}=\dfrac{8}{20}=\dfrac{2}{5}\).
8. з) \(\dfrac{9\cdot4+6\cdot4}{8\cdot81-8\cdot56}=\dfrac{4(9+6)}{8(81-56)}=\dfrac{60}{200}=\dfrac{3}{10}\).
9. и) \(\dfrac{12\cdot5-12\cdot3}{12\cdot4}=\dfrac{12(5-3)}{12\cdot4}=\dfrac{2}{4}=\dfrac{1}{2}\).
10. к) \(\dfrac{2\cdot24+5\cdot6}{25\cdot64-25\cdot4}=\dfrac{78}{25(64-4)}=\dfrac{78}{1500}=\dfrac{13}{250}\).
11. л) \(\dfrac{64\cdot8+64\cdot10}{32\cdot24+32\cdot48}=\dfrac{64(8+10)}{32(24+48)}=\dfrac{2\cdot18}{72}=\dfrac{1}{2}\).
12. м) \(\dfrac{61\cdot2+61\cdot30}{61+61\cdot3}=\dfrac{61(2+30)}{61(1+3)}=\dfrac{32}{4}=8\).

Ответ: а) \(\dfrac{27}{14}\); б) \(\dfrac{3}{10}\); в) \(\dfrac{1}{6}\); г) \(\dfrac{10}{3}\); д) \(\dfrac{94}{71}\); е) \(\dfrac{2}{15}\); ж) \(\dfrac{2}{5}\); з) \(\dfrac{3}{10}\); и) \(\dfrac{1}{2}\); к) \(\dfrac{13}{250}\); л) \(\dfrac{1}{2}\); м) \(8\).