Найдите значение выражения -1\6*4,2-(5\8-1)

- 1 / 6 * 4 , 2 - ( 5 / 8 - 1 ) = - 1 / 6 * 4 целых 2 / 10 - ( 5 / 8 - 1 ) = - 1 / 6 * 4 целых 1 / 5 - ( 5 / 8 - 1 ) = - 1 / 6 * ( 4 * 5 + 1 ) / 5 - ( 5 / 8 - 1 ) = - 1 / 6 * ( 20 + 1 ) / 5 - ( 5 / 8 - 1 ) = - 1 / 6 * 21 / 5 - ( 5 / 8 - 1 ) = - ( 1 * 21 ) / ( 6 * 5 ) - ( 5 / 8 - 1 ) = - 21 / 30 - ( 5 / 8 - 1 ) = - (3 * 7 ) / ( 3 * 10 ) - ( 5 / 8 - 1 ) = - (1 * 7 ) / ( 1 * 10 ) - ( 5 / 8 - 1 ) = - 7 / 10 - ( 5 / 8 - 1 ) = - 7 / 10 - 5 / 8 + 1 = ( - 7 * 8 - 5 * 10 + 1 * 80 ) / 80 = ( - 56 - 50 + 80 ) / 80 = - 26 / 80 = - 13 / 40.