C.2.30. Решите уравнение: 1) 3x - 2(7 - 4x) = 5(1 - 6x); 2) 2,5(x - 3) + 7,5x = -4(2x + 1); 3) -1,5(3x + 2) - 8(x + 1) = 15; 4) 5(x - 8) + 7(6 + 4x) = -13.

1) \(3x - 2(7 - 4x) = 5(1 - 6x)\) \(3x - 14 + 8x = 5 - 30x\) \(11x - 14 = 5 - 30x\) \(11x + 30x = 5 + 14\) \(41x = 19\) \(x = \frac{19}{41}\) 2) \(2,5(x - 3) + 7,5x = -4(2x + 1)\) \(2,5x - 7,5 + 7,5x = -8x - 4\) \(10x - 7,5 = -8x - 4\) \(10x + 8x = -4 + 7,5\) \(18x = 3,5\) \(x = \frac{3,5}{18} = \frac{35}{180} = \frac{7}{36}\) 3) \(-1,5(3x + 2) - 8(x + 1) = 15\) \(-4,5x - 3 - 8x - 8 = 15\) \(-12,5x - 11 = 15\) \(-12,5x = 15 + 11\) \(-12,5x = 26\) \(x = \frac{26}{-12,5} = -\frac{260}{125} = -\frac{52}{25} = -2,08\) 4) \(5(x - 8) + 7(6 + 4x) = -13\) \(5x - 40 + 42 + 28x = -13\) \(33x + 2 = -13\) \(33x = -13 - 2\) \(33x = -15\) \(x = -\frac{15}{33} = -\frac{5}{11}\)