Ответ:
1. Вычисления:
- \(\textbf{а)}\) \[ \frac{0,85 \cdot 3,38 \cdot 0,9}{6,8 \cdot 1,17} = \frac{0,85 \cdot 3,38 \cdot 0,9}{2 \cdot 0,85 \cdot 3 \cdot 0,39} = \frac{3,38 \cdot 0,9}{2 \cdot 3,38 \cdot 0,39} = \frac{0,9}{2 \cdot 0,39} = \frac{0,9}{0,78} = \frac{90}{78} = \frac{15}{13} \] \(\textbf{Ответ: } \frac{15}{13}\)
- \(\textbf{б)}\) \[ 14 - 13,2 : \left(3\frac{11}{21} - 2\frac{4}{15}\right) = 14 - 13,2 : \left(\frac{74}{21} - \frac{34}{15}\right) \] \[ \frac{74}{21} - \frac{34}{15} = \frac{74 \cdot 5 - 34 \cdot 7}{105} = \frac{370 - 238}{105} = \frac{132}{105} = \frac{44}{35} \] \[ 14 - 13,2 : \frac{44}{35} = 14 - \frac{132}{10} \cdot \frac{35}{44} = 14 - \frac{3 \cdot 44}{10} \cdot \frac{35}{44} = 14 - \frac{3 \cdot 35}{10} = 14 - \frac{105}{10} = 14 - 10,5 = 3,5 \] \(\textbf{Ответ: } 3,5\)
- \(\textbf{в)}\) \[ \left(8\frac{7}{12} - 2\frac{17}{36}\right) \cdot 2,7 - 4\frac{1}{3} : 0,65 = \left(\frac{103}{12} - \frac{89}{36}\right) \cdot 2,7 - \frac{13}{3} : \frac{65}{100} \] \[ \frac{103}{12} - \frac{89}{36} = \frac{103 \cdot 3 - 89}{36} = \frac{309 - 89}{36} = \frac{220}{36} = \frac{55}{9} \] \[ \frac{55}{9} \cdot 2,7 = \frac{55}{9} \cdot \frac{27}{10} = \frac{55 \cdot 3}{10} = \frac{11 \cdot 3}{2} = \frac{33}{2} = 16,5 \] \[ \frac{13}{3} : \frac{65}{100} = \frac{13}{3} \cdot \frac{100}{65} = \frac{13 \cdot 100}{3 \cdot 5 \cdot 13} = \frac{100}{15} = \frac{20}{3} \] \[ 16,5 - \frac{20}{3} = \frac{33}{2} - \frac{20}{3} = \frac{33 \cdot 3 - 20 \cdot 2}{6} = \frac{99 - 40}{6} = \frac{59}{6} \] \(\textbf{Ответ: } \frac{59}{6}\)
