г) 3 3. (19+2y) = 99 д) 7. (15-2y) = 97 - 76 e) 2. (67-3y - y) = 30

Решение:

1. г) 3 * (19 + 2y) = 99
   57 + 6y = 99
   6y = 99 - 57
   6y = 42
   y = 42 / 6
   y = 7
2. д) 7 * (15 - 2y) = 97 - 76
   105 - 14y = 21
   105 - 21 = 14y
   84 = 14y
   y = 84 / 14
   y = 6
3. e) 2 * (67 - 3y - y) = 30
   2 * (67 - 4y) = 30
   134 - 8y = 30
   134 - 30 = 8y
   104 = 8y
   y = 104 / 8
   y = 13

Ответ: г) y = 7; д) y = 6; e) y = 13.