№18. Решите уравнения: 1) x : 19 = 26; 2) 238 : x = 14; 3) (x + 7) : 8 = 9; 4) x : 8 + 7 = 9; 5) 48 : (x + 3) = 6; 6) 48 : x + 3 = 6.

Решение:

1. \( x : 19 = 26 \)
   \( x = 26 \cdot 19 \)
   \( x = 494 \)
2. \( 238 : x = 14 \)
   \( x = 238 : 14 \)
   \( x = 17 \)
3. \( (x + 7) : 8 = 9 \)
   \( x + 7 = 9 \cdot 8 \)
   \( x + 7 = 72 \)
   \( x = 72 - 7 \)
   \( x = 65 \)
4. \( x : 8 + 7 = 9 \)
   \( x : 8 = 9 - 7 \)
   \( x : 8 = 2 \)
   \( x = 2 \cdot 8 \)
   \( x = 16 \)
5. \( 48 : (x + 3) = 6 \)
   \( x + 3 = 48 : 6 \)
   \( x + 3 = 8 \)
   \( x = 8 - 3 \)
   \( x = 5 \)
6. \( 48 : x + 3 = 6 \)
   \( 48 : x = 6 - 3 \)
   \( 48 : x = 3 \)
   \( x = 48 : 3 \)
   \( x = 16 \)

Ответ: 1) 494; 2) 17; 3) 65; 4) 16; 5) 5; 6) 16.