№3. Решите уравнения: 3 11 1)x+=12 4 14 1 2)x-15=6';

Ответ: x = 2/12 = 1/6; x = 19/30

1) \[x + \frac{3}{4} = \frac{11}{12}\]

\[x = \frac{11}{12} - \frac{3}{4}\]

\[x = \frac{11}{12} - \frac{3 \cdot 3}{4 \cdot 3}\]

\[x = \frac{11}{12} - \frac{9}{12}\]

\[x = \frac{11 - 9}{12}\]

\[x = \frac{2}{12} = \frac{1}{6}\]

2) \[x - \frac{14}{15} = \frac{1}{6}\]

\[x = \frac{1}{6} + \frac{14}{15}\]

\[x = \frac{1 \cdot 5}{6 \cdot 5} + \frac{14 \cdot 2}{15 \cdot 2}\]

\[x = \frac{5}{30} + \frac{28}{30}\]

\[x = \frac{5 + 28}{30}\]

\[x = \frac{33}{30} = \frac{11}{10}\]

Ответ: x = 1/6; x = 11/10