(-8,6 + 4,2) : (-2 12/17) = 1 целая 72/115
1) -8,6 + 4,2 = -4,4 = - 4 целых 2/5 = - 22/5
2) - 22/5 : (-2 12/17) = - 22/5 : (-46/17) = - 22/5 * (-17/46) = (11*17)/(5*23) = 187/115 = 1 целая 72/115
Пояснения:
2 целых 12/17 = (2*17+12)/17 = 46/17
(-) * (-) = (+)
(4 1/4 - 3 5/6) * (-1 2/13) = - 25/52
1) 4 1/4 - 3 5/6 = 4 3/12 - 3 10/12 = 3 15/12 - 3 10/12 = 5/12
2) 5/12 * (-1 2/13) = 5/12 * (-15/13) = - (5*5)/(4*13) = - 25/52
Пояснения:
1 целая 2/13 = (1*13+2)/13 = 15/13
(+) * (-) = (-)