Question

В)5/21+11/14+9/28 г)19/15+6/5+13/30

Answer 1

Ответ:

в) $\frac{5}{21} + \frac{11}{14} + \frac{9}{28} = \frac{5\cdot4}{21\cdot4} + \frac{11\cdot6}{14\cdot6} + \frac{9\cdot3}{28\cdot3} = \frac{20+66+27}{84} = \frac{113}{84} = 1\frac{29}{84}$

г) $\frac{19}{15} + \frac{6}{5} + \frac{13}{30} = \frac{19\cdot2}{15\cdot2} + \frac{6\cdot6}{5\cdot6} + \frac{13}{30} = \frac{38+36+13}{30} = \frac{87}{30} = 2\frac{27}{30} = 2\frac{9}{10} = 2,9$

Answer 2

Решение приложено на фото.

Answer 3

To solve the given expressions, you need to find the common denominator for each set of fractions and then add them up. Let's go through each one step by step:

а) 5/21 + 11/14 + 9/28

To add these fractions, we first need to find a common denominator for 21, 14, and 28. The smallest common multiple of these numbers is 84.

Now, we convert each fraction to have a denominator of 84:

5/21 = (5/21) * (4/4) = 20/84 11/14 = (11/14) * (6/6) = 66/84 9/28 = (9/28) * (3/3) = 27/84

Now that all fractions have the same denominator, we can add them up:

5/21 + 11/14 + 9/28 = 20/84 + 66/84 + 27/84 = (20 + 66 + 27) / 84 = 113/84

b) 19/15 + 6/5 + 13/30

For these fractions, the common denominator is 30. Let's convert each fraction:

19/15 = (19/15) * (2/2) = 38/30 6/5 = (6/5) * (6/6) = 36/30 13/30 (already in terms of the common denominator)

Now, add them up:

19/15 + 6/5 + 13/30 = 38/30 + 36/30 + 13/30 = (38 + 36 + 13) / 30 = 87/30

So the simplified results are:

a) 113/84 b) 87/30