1) (y+8)*(-7)=14
-7у - 56 = 14
-7у = 14 + 56
- 7у = 70
у = 70 : (-7)
у = - 10
2) 3*(5-x)+13=4*(3x-8)
15 - 3х + 13 = 12х - 24
-3х - 12х = -24 - 15 - 13
- 15х = -52
х = 52 : 15
х = 3,4
3) 3/7-1/4x=5 3/7-4x
12/28 - 7/28х = 5 12/28 - 4х
- 7/28х + 4х = 5 12/28 - 12/28
3 21/28х = 5
3 3/4х = 5
х = 5 : 3 3/4
х = 4/3
х = 1 1/3