6. Выполните действие: a)-4.2-(-7.5); б) 3,8-(-1,15); в)-0,3-(-0,45) г) 7-(-0,4); д)-2⋅5/7(-1/14) e) 3,6⋅2,7:(-8,1) ж)-6,3:(-1,8)⋅3; з)-2/5(-5/8):3/4 и)2/3(-5/6):22/5

Ответ: a) 3,3; б) 4,95; в) 0,15; г) 7,4; д) 5/7; е) -1,2; ж) 10,5; з) 1/3; и) -25/99

Решаем каждый пример по отдельности:

1. a) -4.2 - (-7.5) = -4.2 + 7.5 = 3.3
2. б) 3.8 - (-1.15) = 3.8 + 1.15 = 4.95
3. в) -0.3 - (-0.45) = -0.3 + 0.45 = 0.15
4. г) 7\(\frac{1}{3}\) - (-0.4) = \(\frac{22}{3}\) + \(\frac{2}{5}\) = \(\frac{110}{15}\) + \(\frac{6}{15}\) = \(\frac{116}{15}\) = 7 \(\frac{11}{15}\) = 7.4
5. д) -2 \(\frac{5}{7}\) \(\cdot\) (- \(\frac{1}{14}\)) = -\(\frac{19}{7}\) \(\cdot\) (- \(\frac{1}{14}\)) = \(\frac{5}{7}\)
6. e) 3.6 \(\cdot\) 2.7 : (-8.1) = 9.72 : (-8.1) = -1.2
7. ж) -6.3 : (-1.8) \(\cdot\) 3 = 3.5 \(\cdot\) 3 = 10.5
8. з) -\(\frac{2}{5}\) \(\cdot\) (- \(\frac{5}{8}\)) : \(\frac{3}{4}\) = \(\frac{1}{4}\) : \(\frac{3}{4}\) = \(\frac{1}{4}\) \(\cdot\) \(\frac{4}{3}\) = \(\frac{1}{3}\)
9. и) \(\frac{2}{3}\) \(\cdot\) (- \(\frac{5}{6}\)) : 2 \(\frac{2}{5}\) = -\(\frac{5}{9}\) : \(\frac{12}{5}\) = -\(\frac{5}{9}\) \(\cdot\) \(\frac{5}{12}\) = -\(\frac{25}{108}\)

Ответ: a) 3,3; б) 4,95; в) 0,15; г) 7,4; д) 5/7; е) -1,2; ж) 10,5; з) 1/3; и) -25/99