Алгебра 7 класс. Повторение. "Уравнения".

Решение:

Решим уравнения:

1. \( 2x - 13 = 11 \)
   \( 2x = 11 + 13 \)
   \( 2x = 24 \)
   \( x = \frac{24}{2} \)
   \( x = 12 \)
2. \( 14x = 210 \)
   \( x = \frac{210}{14} \)
   \( x = 15 \)
3. \( 2,5 - x = 1,2 \)
   \( -x = 1,2 - 2,5 \)
   \( -x = -1,3 \)
   \( x = 1,3 \)
4. \( 6x + 42 = 36 \)
   \( 6x = 36 - 42 \)
   \( 6x = -6 \)
   \( x = \frac{-6}{6} \)
   \( x = -1 \)
5. \( 6x + 5 = 19 - x \)
   \( 6x + x = 19 - 5 \)
   \( 7x = 14 \)
   \( x = \frac{14}{7} \)
   \( x = 2 \)
6. \( 6(x+2) = 12 \)
   \( x+2 = \frac{12}{6} \)
   \( x+2 = 2 \)
   \( x = 2 - 2 \)
   \( x = 0 \)
7. \( \frac{3}{2}x = 15 \)
   \( x = 15 \cdot \frac{2}{3} \)
   \( x = 5 \cdot 2 \)
   \( x = 10 \)
8. \( -\frac{x}{4} = \frac{15}{2} \)
   \( x = \frac{15}{2} \cdot (-4) \)
   \( x = 15 \cdot (-2) \)
   \( x = -30 \)
9. \( 4 - 3x = -11 \)
   \( -3x = -11 - 4 \)
   \( -3x = -15 \)
   \( x = \frac{-15}{-3} \)
   \( x = 5 \)
10. \( 5+2x = -2 \)
    \( 2x = -2 - 5 \)
    \( 2x = -7 \)
    \( x = - \frac{7}{2} \)
11. \( -x + 4,8 = -0,8 \)
    \( -x = -0,8 - 4,8 \)
    \( -x = -5,6 \)
    \( x = 5,6 \)
12. \( 1 - 9x = 0 \)
    \( -9x = -1 \)
    \( x = \frac{-1}{-9} \)
    \( x = \frac{1}{9} \)
13. \( x = 7 \)
14. \( x = -1 \)
15. \( x = -45 \)
16. \( x = -9 \)

Ответ: 12, 15, 1,3, -1, 2, 0, 10, -30, 5, -3,5, 5,6, \( \frac{1}{9} \), 7, -1, -45, -9.