1.1/2+1/3=5/6
5/6+1/6=1
1*24=24
24:5=4 4/5
9/22:15/121=3 3/10
4 4/5-3 3/10=1 1/2
15 3
5 5
1
21 3
7 7
1
2 2
1
14 2
7 7
1
3*5*7*2=210
(16-8)*9=72
(8-4)*9=36
(9:3)*6=18
(13-5)*8=64
7*(3+4)=49
(28+7):5=7
50 - (12 - х) = - 25
50 - 12 + х = - 25
х = - 25 - 50 + 12
х = - 63
Проверка: 50 - (12 - (-63) = - 25
50 - (12 + 63) = - 25
50 - 75 = - 25
- 25 = - 25
Ответ: х = - 63.