2. Решите уравнение: 1) 4y + 2,6 = 10,2; 2) (3,5 + x) · 3 = 21.

1. \(4y + 2.6 = 10.2\)
   \(4y = 10.2 - 2.6 = 7.6\)
   \(y = 7.6 : 4 = 1.9\).
2. \((3.5 + x) \cdot 3 = 21\)
   \(3.5 + x = 21 : 3 = 7\)
   \(x = 7 - 3.5 = 3.5\).

Ответ: 1) \(y = 1,9\); 2) \(x = 3,5\).