Задание 4. Найдите значение выражения 1) 3,4 / (1 - 1/18) 2) 0,8 / (1 + 1/7) 3) 40 * (1/8)^2 - 13 * 1/8

Задание 4

1. \( \frac{3.4}{1-\frac{1}{18}} = \frac{3.4}{\frac{18}{18}-\frac{1}{18}} = \frac{3.4}{\frac{17}{18}} = 3.4 \cdot \frac{18}{17} = \frac{34}{10} \cdot \frac{18}{17} = \frac{2 \cdot 17}{10} \cdot \frac{18}{17} = \frac{2}{10} \cdot 18 = \frac{1}{5} \cdot 18 = \frac{18}{5} = 3.6 \)
2. \( \frac{0.8}{1+\frac{1}{7}} = \frac{0.8}{\frac{7}{7}+\frac{1}{7}} = \frac{0.8}{\frac{8}{7}} = 0.8 \cdot \frac{7}{8} = \frac{8}{10} \cdot \frac{7}{8} = \frac{7}{10} = 0.7 \)
3. \( 40 \cdot \left(\frac{1}{8}\right)^2 - 13 \cdot \frac{1}{8} = 40 \cdot \frac{1}{64} - \frac{13}{8} = \frac{40}{64} - \frac{13}{8} = \frac{5}{8} - \frac{13}{8} = \frac{5-13}{8} = \frac{-8}{8} = -1 \)

Ответ: 1) 3.6; 2) 0.7; 3) -1.