Выполнить действия. a) 2,3-(-8) - 9,8:(6,7 – 8,1) б) $$-3\frac{3}{4} - \left(-8\frac{2}{9} - (-4,5): \frac{9}{14}\right) \cdot 2\frac{1}{4}$$

a) 2,3-(-8) - 9,8:(6,7 – 8,1)

1. 6,7 - 8,1 = -1,4
2. 9,8 : (-1,4) = -7
3. 2,3 - (-8) = 2,3 + 8 = 10,3
4. 10,3 - (-7) = 10,3 + 7 = 17,3

Ответ: 17,3

б) $$-3\frac{3}{4} - \left(-8\frac{2}{9} - (-4,5): \frac{9}{14}\right) \cdot 2\frac{1}{4}$$

1. $$-4,5 : \frac{9}{14} = -\frac{45}{10} : \frac{9}{14} = -\frac{45}{10} \cdot \frac{14}{9} = -\frac{5}{5} \cdot \frac{7}{1} = -7$$
2. $$-8\frac{2}{9} - (-7) = -8\frac{2}{9} + 7 = -1\frac{2}{9} = -\frac{11}{9}$$
3. $$-3\frac{3}{4} = -\frac{15}{4}; \quad 2\frac{1}{4} = \frac{9}{4}$$
4. $$\left(-\frac{11}{9}\right) \cdot \frac{9}{4} = -\frac{11}{4}$$
5. $$- \frac{15}{4} - \left(-\frac{11}{4}\right) = -\frac{15}{4} + \frac{11}{4} = -\frac{4}{4} = -1$$

Ответ: -1