помогите пж Не поможете я труп даю 100 баллов а ​

Пошаговое объяснение:

№1

1) 3/4 - 4/5 = 15/20 - 16/20 = -1/20

2) -1/20 * 7,8 = -1/20 * 78/10 = -1/10 * 39/10 = -39/100

3) 2/3 + 4/7 = 14/21 + 12/21 = 26/21

4) 26/21 * (-7/13) = 2/3 * (-1/1) = -2/3

5) -39/100 - (-2/3) = -39/100 + 2/3 = -117/300 + 200/300 = 83/300

№2

1) 3/7 - 16/21 = 9/21 - 16/21 = -7/21

2) -7/21 * (-2 2/7) = -7/21 * (-16/7) = -1/21 * (-16/1) = 16/21

3) 11/15 + 0,3 = 11/15 + 3/10 = 22/30 + 9/30 = 31/30

4) 31/30 : (-12 2/5) = 31/30 : (-62/5) = 31/30 * (-5/62) = 1/6 * (-1/2) = -1/12

5) 16/21 + (-1/12) = 16/21 - 1/12 = 64/84 - 7/84 = 57/84 = 19/28