27. Подчеркните верные равенства.

Решение:

Проверим каждое равенство:

а) \(\underline{\frac{1}{2} = \frac{3}{6}}\): \(1 \times 6 = 2 \times 3\) → \(6 = 6\). Верно.

б) \(\underline{\frac{3}{5} = \frac{9}{15}}\): \(3 \times 15 = 5 \times 9\) → \(45 = 45\). Верно.

в) \(\underline{\frac{4}{9} = \frac{12}{39}}\): \(4 \times 39 = 9 \times 12\) → \(156 \neq 108\). Неверно.

г) \(\underline{\frac{2}{7} = \frac{6}{14}}\): \(2 \times 14 = 7 \times 6\) → \(28 = 42\). Неверно.

д) \(\underline{\frac{1}{9} = \frac{3}{27}}\): \(1 \times 27 = 9 \times 3\) → \(27 = 27\). Верно.

е) \(\underline{\frac{5}{11} = \frac{20}{55}}\): \(5 \times 55 = 11 \times 20\) → \(275 = 220\). Неверно.

ж) \(\underline{\frac{1}{25} = \frac{3}{75}}\): \(1 \times 75 = 25 \times 3\) → \(75 = 75\). Верно.

з) \(\underline{\frac{3}{13} = \frac{12}{23}}\): \(3 \times 23 = 13 \times 12\) → \(69 \neq 156\). Неверно.

и) \(\underline{\frac{7}{8} = \frac{49}{56}}\): \(7 \times 56 = 8 \times 49\) → \(392 = 392\). Верно.

к) \(\underline{\frac{2}{5} = \frac{20}{100}}\): \(2 \times 100 = 5 \times 20\) → \(200 \neq 100\). Неверно.

Подчеркнуты верные равенства:

\(\frac{1}{2} = \frac{3}{6}\)

\(\frac{3}{5} = \frac{9}{15}\)

\(\frac{1}{9} = \frac{3}{27}\)

\(\frac{1}{25} = \frac{3}{75}\)

\(\frac{7}{8} = \frac{49}{56}\)