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Решение.

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[tex]1)\ \ \displaystyle \bf 4\frac{1}{5}:\frac{7}{15}:\frac{1}{3}=\frac{21}{5}\cdot \frac{15}{7}:\frac{1}{3}=\frac{3\cdot 3}{1\cdot 1}\cdot \frac{3}{1}=27\\\\\\2)\ \ 4\frac{1}{5}:\Big(\frac{7}{15}:\frac{1}{3}\Big)=\frac{21}{5}:\Big(\frac{7}{15}\cdot \frac{3}{1}\Big)=\frac{21}{5}:\frac{7}{5}=\frac{21}{5}\cdot \frac{5}{7}=\frac{21}{7}=3[/tex]

[tex]\bf \displaystyle 3)\ \ \Big(5\frac{8}{9}:1\frac{17}{36}+1\frac{1}{4}\Big):4\frac{1}{5}=\Big(\frac{53}{9}:\frac{53}{36}+\frac{5}{4}\Big):\frac{21}{5}=\\\\\\=\Big(\frac{53}{9}\cdot \frac{36}{53}+\frac{5}{4}\Big)\cdot \frac{5}{21}=\Big(\frac{36}{9}+\frac{5}{4}\Big)\cdot \frac{5}{21}=\Big(4+\frac{5}{4}\Big)\cdot \frac{5}{21}=\frac{16+5}{4}\cdot \frac{5}{21}=\\\\\\=\frac{21}{4}\cdot \frac{5}{21}=\frac{5}{4}=1\frac{1}{4}=1,25[/tex]

[tex]\displaystyle \bf 4)\ \ \Big(2\frac{1}{4}+4\frac{5}{6}\Big):3\frac{2}{5}-\frac{3}{4}:\frac{3}{5}=\Big(\frac{9}{4}+\frac{29}{6}\Big):\frac{17}{5}-\frac{3}{4}\cdot \frac{5}{3}=\\\\\\=\frac{9\cdot 3+29\cdot 2}{12}\cdot \frac{5}{17}-\frac{5}{4}=\frac{85}{12}\cdot \frac{5}{17}-\frac{5}{4}=\frac{5\cdot 17}{12}\cdot \frac{5}{17}-\frac{5}{4}=\\\\\\=\frac{25}{12}-\frac{5}{4}=\frac{25-5\cdot 3}{12}=\frac{10}{12}=\frac{5}{6}[/tex]  

Пошаговое объяснение:

№1

1) 4. 1/5 : 7/15 = 21/5 : 7/15 = 21/5 * 15/7 = 3/1 * 3/1 = 9/1 = 9

2) 9 : 1/3 = 9 * 3/1 = 27/1 = 27

№2

1) 7/15 : 1/3 = 7/15 * 3/1 = 7/5 * 1/1 = 7/5

2) 4. 1/5 : 7/5 = 21/5 : 7/5 = 21/5 * 5/7 = 3/1 * 1/1 = 3/1 = 3

№3

1) 5. 8/9 : 1. 17/36 = 53/9 : 53/36 = 53/9 * 36/53 = 1/1 * 4/1 = 4/1 = 4

2) 4 + 1. 1/4 = 5. 1/4

3) 5. 1/4 : 4. 1/5 = 21/4 : 21/5 = 21/4 * 5/21 = 1/4 * 5/1 = 5/4 = 1. 1/4

№4

1) 2. 1/4 + 4. 5/6 = 2. 3/12 + 4. 10/12 = 6. 13/12 = 7. 1/12

2) 7. 1/12 : 3. 2/5 = 85/12 : 17/5 = 85/12 * 5/17 = 5/12 * 5/1 = 25/12 = 2. 1/12

3) 3/4 : 3/5 = 3/4 * 5/3 = 1/4 * 5/1 = 5/4 = 1. 1/4

4) 2. 1/12 - 1. 1/4 = 2. 1/12 - 1. 3/12 = 1. 13/12 - 1. 3/12 = 10/12 = 5/6