№3. Решите уравнение: 1) 3x + 18 = 5x - 4 2) 6x - 2(2x + 9) + 1 = -6x + 9 3) \frac{6x - 6}{5} = \frac{3x + 4}{10}

Решение:

1. \[3x + 18 = 5x - 4\]\[18 + 4 = 5x - 3x\]\[22 = 2x\]\[x = \frac{22}{2}\]\[x = 11\]
2. \[6x - 2(2x + 9) + 1 = -6x + 9\]\[6x - 4x - 18 + 1 = -6x + 9\]\[2x - 17 = -6x + 9\]\[2x + 6x = 9 + 17\]\[8x = 26\]\[x = \frac{26}{8}\]\[x = \frac{13}{4}\]\[x = 3.25\]
3. \[\frac{6x - 6}{5} = \frac{3x + 4}{10}\]\[10 \cdot \frac{6x - 6}{5} = 10 \cdot \frac{3x + 4}{10}\]\[2(6x - 6) = 3x + 4\]\[12x - 12 = 3x + 4\]\[12x - 3x = 4 + 12\]\[9x = 16\]\[x = \frac{16}{9}\]