3. Решите уравнения: а) 649 − x = 25 · 22; б) 36 · x + 472 = 868; в) 560 : x + 318 = 338; г) 750 − 480 : y = 690.

1. \(649 - x = 25 \cdot 22\)
   \(649 - x = 550\)
   \(x = 649 - 550 = 99\).
2. \(36 \cdot x + 472 = 868\)
   \(36 \cdot x = 868 - 472 = 396\)
   \(x = 396 : 36 = 11\).
3. \(560 : x + 318 = 338\)
   \(560 : x = 338 - 318 = 20\)
   \(x = 560 : 20 = 28\).
4. \(750 - 480 : y = 690\)
   \(480 : y = 750 - 690 = 60\)
   \(y = 480 : 60 = 8\).

Ответ: а) \(x = 99\); б) \(x = 11\); в) \(x = 28\); г) \(y = 8\).