1) \(\frac{24}{4-4.8} = \frac{24}{-0.8} = -30\)
2) \(\frac{27}{3-4.8} = \frac{27}{-1.8} = -15\)
3) \(\frac{0.8}{1-\frac{1}{9}} = \frac{0.8}{\frac{8}{9}} = \frac{0.8 \cdot 9}{8} = 0.1 \cdot 9 = 0.9\)
4) \(\frac{1.5}{1+\frac{1}{5}} = \frac{1.5}{\frac{6}{5}} = \frac{1.5 \cdot 5}{6} = \frac{7.5}{6} = 1.25\)
5) \(-12 - (-8.6) - 9.4 = -12 + 8.6 - 9.4 = -3.4 - 9.4 = -12.8\)
6) \(-7 - (-4.7) - 6.8 = -7 + 4.7 - 6.8 = -2.3 - 6.8 = -9.1\)
7) \(12 - 5 - (-1.7) = 12 - 5 + 1.7 = 7 + 1.7 = 8.7\)
Ответ: 1) \(-30\); 2) \(-15\); 3) \(0.9\); 4) \(1.25\); 5) \(-12.8\); 6) \(-9.1\); 7) \(8.7\)