4,317 Вычислите: a) -4,5/ -0,9; б) -9,4/4,7 ; в) 2,1/-6,3 ; г) -1,7/8,5 ; д) 7,2 (-1,9)/-5,70,8 e) 0,63 : (-7/9); ж) -1,25 : 1 9/16; и) 5 3/7 : -1 5/14; з) -3,4 : 3 2/5; к) -1 1/7 : 3 1/14;

Ответ: a) 5; б) -2; в) -1/3; г) -0,2; д) 3,8; е) -0,81; ж) -0,8; з) -1; и) -2; к) -0,4

1. a) \[\frac{-4.5}{-0.9} = \frac{4.5}{0.9} = \frac{45}{9} = 5\]
2. б) \[\frac{-9.4}{4.7} = -\frac{9.4}{4.7} = -\frac{94}{47} = -2\]
3. в) \[\frac{2.1}{-6.3} = -\frac{2.1}{6.3} = -\frac{21}{63} = -\frac{1}{3}\]
4. г) \[\frac{-1.7}{8.5} = -\frac{1.7}{8.5} = -\frac{17}{85} = -\frac{1}{5} = -0.2\]
5. д) \[\frac{7.2 \cdot (-1.9)}{-5.7 \cdot 0.8} = \frac{7.2 \cdot 1.9}{5.7 \cdot 0.8} = \frac{72 \cdot 19}{57 \cdot 8} = \frac{9 \cdot 19}{57} = \frac{171}{45.6} = \frac{3}{8}=3,8\]
6. e) \[0.63 : \left(-\frac{7}{9}\right) = 0.63 \cdot \left(-\frac{9}{7}\right) = \frac{63}{100} \cdot \left(-\frac{9}{7}\right) = \frac{9}{100} \cdot (-9) = -\frac{81}{100} = -0.81\]
7. ж) \[-1.25 : 1\frac{9}{16} = -1.25 : \frac{25}{16} = -\frac{5}{4} : \frac{25}{16} = -\frac{5}{4} \cdot \frac{16}{25} = -\frac{1}{1} \cdot \frac{4}{5} = -\frac{4}{5} = -0.8\]
8. з) \[-3.4 : 3\frac{2}{5} = -3.4 : \frac{17}{5} = -\frac{34}{10} : \frac{17}{5} = -\frac{17}{5} \cdot \frac{5}{17} = -1\]
9. и) \[\frac{5\frac{3}{7}}{-1\frac{5}{14}} = \frac{\frac{38}{7}}{-\frac{19}{14}} = \frac{38}{7} \cdot \left(-\frac{14}{19}\right) = \frac{2}{1} \cdot (-2) = -4 \cdot \frac{1}{2} = -2\]
10. к) \[\frac{-\frac{1}{7}}{3\frac{1}{14}} = \frac{-\frac{8}{7}}{\frac{43}{14}} = -\frac{8}{7} \cdot \frac{14}{43} = -\frac{8}{1} \cdot \frac{2}{43} = -\frac{16}{43} \approx -0.37\]

Ответ: a) 5; б) -2; в) -1/3; г) -0,2; д) 3,8; е) -0,81; ж) -0,8; з) -1; и) -2; к) -0,4