Тема. «Решение уравнений» (3 уровень) Решить уравнение: 1) (5x-3)+(7x-4)=8-(15-11x), 2) (4x+3)-(10x+11)=7+(13-4x), 3) (7-5x)-(8-4x)+(5x+6)=8, 4) (3-2x)+(4-3x)+(5-5x)=12+7x.

Решение:

1. \( (5x-3)+(7x-4)=8-(15-11x) \)
   \( 12x - 7 = 8 - 15 + 11x \)
   \( 12x - 11x = -7 + 7 \)
   \( x = 0 \)
2. \( (4x+3)-(10x+11)=7+(13-4x) \)
   \( 4x + 3 - 10x - 11 = 7 + 13 - 4x \)
   \( -6x - 8 = 20 - 4x \)
   \( -6x + 4x = 20 + 8 \)
   \( -2x = 28 \)
   \( x = -14 \)
3. \( (7-5x)-(8-4x)+(5x+6)=8 \)
   \( 7 - 5x - 8 + 4x + 5x + 6 = 8 \)
   \( 4x + 5 = 8 \)
   \( 4x = 3 \)
   \( x = \frac{3}{4} \)
4. \( (3-2x)+(4-3x)+(5-5x)=12+7x \)
   \( 3 - 2x + 4 - 3x + 5 - 5x = 12 + 7x \)
   \( 12 - 10x = 12 + 7x \)
   \( -10x - 7x = 12 - 12 \)
   \( -17x = 0 \)
   \( x = 0 \)

Ответ: 1) x = 0; 2) x = -14; 3) x = \(\frac{3}{4}\); 4) x = 0.