Найдите корень уравнения: 15 − x · 2 = 9; 1015 : x − 7 = 22; x : 15 + 150 = 400

1. \(15 - x \cdot 2 = 9\)
   \(x \cdot 2 = 15 - 9 = 6\)
   \(x = 6 : 2 = 3\).
2. \(1015 : x - 7 = 22\)
   \(1015 : x = 22 + 7 = 29\)
   \(x = 1015 : 29 = 35\).
3. \(x : 15 + 150 = 400\)
   \(x : 15 = 400 - 150 = 250\)
   \(x = 250 \cdot 15 = 3750\).

Ответ: 1) \(x = 3\); 2) \(x = 35\); 3) \(x = 3750\).