Вариант 4 Решите уравнения: 1. 9x + 4 = 48 - 2x 2.8 - 4x = 2x – 16 3. 0,4x + 3,8 = 2,6 - 0,8x 4. 4*(x – 6) = x - 9 5. 6 - 3*(x + 1) = 7 - 2x 6. 3,5 - y = 8*(y + 2,8) 7. 8*(5 – 3x) = 6* (2 - 4x) + 7

Решение:

1. \( 9x + 4 = 48 - 2x \)
   \( 9x + 2x = 48 - 4 \)
   \( 11x = 44 \)
   \( x = \frac{44}{11} \)
   \( x = 4 \)
2. \( 8 - 4x = 2x - 16 \)
   \( 8 + 16 = 2x + 4x \)
   \( 24 = 6x \)
   \( x = \frac{24}{6} \)
   \( x = 4 \)
3. \( 0,4x + 3,8 = 2,6 - 0,8x \)
   \( 0,4x + 0,8x = 2,6 - 3,8 \)
   \( 1,2x = -1,2 \)
   \( x = \frac{-1,2}{1,2} \)
   \( x = -1 \)
4. \( 4(x - 6) = x - 9 \)
   \( 4x - 24 = x - 9 \)
   \( 4x - x = -9 + 24 \)
   \( 3x = 15 \)
   \( x = \frac{15}{3} \)
   \( x = 5 \)
5. \( 6 - 3(x + 1) = 7 - 2x \)
   \( 6 - 3x - 3 = 7 - 2x \)
   \( 3 - 3x = 7 - 2x \)
   \( -3x + 2x = 7 - 3 \)
   \( -x = 4 \)
   \( x = -4 \)
6. \( 3,5 - y = 8(y + 2,8) \)
   \( 3,5 - y = 8y + 22,4 \)
   \( 3,5 - 22,4 = 8y + y \)
   \( -18,9 = 9y \)
   \( y = \frac{-18,9}{9} \)
   \( y = -2,1 \)
7. \( 8(5 - 3x) = 6(2 - 4x) + 7 \)
   \( 40 - 24x = 12 - 24x + 7 \)
   \( 40 - 24x = 19 - 24x \)
   \( 40 = 19 \)

Ответ: 1. x = 4; 2. x = 4; 3. x = -1; 4. x = 5; 5. x = -4; 6. y = -2,1; 7. Решений нет.