15 x (-7) = -105
(-84) : (-14) = 6
(- 0,9) x (4,1) = -3,69
-4 4/9 : (-3 1/3) = -40/9 : (-10/3) = -40/9 * (-3/10) = 4/3 = 1 1/3
А) (-29) + 12 + (-40) + (-31) +38 = -50
Б) (-6/13) х 4.5/6 x 13/6 = (-6/13) * (45/60) * (13/6) = (-6/13) * (3/4) * (13/6) = -3/4 = -0.75
В) (-11/15) x 4,2 – 4,2 x 4/15 = 4,2 * (-11/15 - 4/15) = 4.2 * (-15/15) = 4.2 * (-1) = -4.2
А) -1,6 a = - 6,48 => a = -6.48 / -1.6 = 4.05
Б) в : (-2,4) = - 4,8 => b = -4.8 * (-2.4) = 11.52
5/12 = 0.41(6) ≈ 0.42
6 2/9 = 6.(2) ≈ 6.22
Ответ: смотри решение выше