Вариант 2: Найди значение х

Решение:

1. \( 4x + 9 = x + 18 \)
   \( 4x - x = 18 - 9 \)
   \( 3x = 9 \)
   \( x = \frac{9}{3} \)
   \( x = 3 \)
2. \( 6x - 5 = 2x + 7 \)
   \( 6x - 2x = 7 + 5 \)
   \( 4x = 12 \)
   \( x = \frac{12}{4} \)
   \( x = 3 \)
3. \( 7x + 8 = 5x + 2 \)
   \( 7x - 5x = 2 - 8 \)
   \( 2x = -6 \)
   \( x = \frac{-6}{2} \)
   \( x = -3 \)
4. \( 5x + 1 = x + 9 \)
   \( 5x - x = 9 - 1 \)
   \( 4x = 8 \)
   \( x = \frac{8}{4} \)
   \( x = 2 \)
5. \( 8x - 6 = 3x + 4 \)
   \( 8x - 3x = 4 + 6 \)
   \( 5x = 10 \)
   \( x = \frac{10}{5} \)
   \( x = 2 \)
6. \( 9x + 7 = 4x + 32 \)
   \( 9x - 4x = 32 - 7 \)
   \( 5x = 25 \)
   \( x = \frac{25}{5} \)
   \( x = 5 \)
7. \( 3x - 4 = 2x - 9 \)
   \( 3x - 2x = -9 + 4 \)
   \( x = -5 \)
8. \( 2x + 5 = 6x - 7 \)
   \( 5 + 7 = 6x - 2x \)
   \( 12 = 4x \)
   \( x = \frac{12}{4} \)
   \( x = 3 \)
9. \( 7x - 3 = x - 15 \)
   \( 7x - x = -15 + 3 \)
   \( 6x = -12 \)
   \( x = \frac{-12}{6} \)
   \( x = -2 \)
10. \( 5x + 6 = 3x - 8 \)
    \( 5x - 3x = -8 - 6 \)
    \( 2x = -14 \)
    \( x = \frac{-14}{2} \)
    \( x = -7 \)
11. \( 6x - 9 = 4x + 3 \)
    \( 6x - 4x = 3 + 9 \)
    \( 2x = 12 \)
    \( x = \frac{12}{2} \)
    \( x = 6 \)
12. \( 8x + 2 = 6x + 10 \)
    \( 8x - 6x = 10 - 2 \)
    \( 2x = 8 \)
    \( x = \frac{8}{2} \)
    \( x = 4 \)

Ответ: 1. 3; 2. 3; 3. -3; 4. 2; 5. 2; 6. 5; 7. -5; 8. 3; 9. -2; 10. -7; 11. 6; 12. 4.