9. Решите уравнение:
а) $$(2x - 3)^2 - (2x + 5)(2x + 1) = 0$$
$$4x^2 - 12x + 9 - (4x^2 + 2x + 10x + 5) = 0$$
$$4x^2 - 12x + 9 - 4x^2 - 12x - 5 = 0$$
$$-24x + 4 = 0$$
$$-24x = -4$$
$$x = \frac{-4}{-24}$$
$$x = \frac{1}{6}$$
Ответ: $$x = \frac{1}{6}$$.
б) $$(x - 1)(x + 2) - (x + 4)^2 = 0$$
$$x^2 + 2x - x - 2 - (x^2 + 8x + 16) = 0$$
$$x^2 + x - 2 - x^2 - 8x - 16 = 0$$
$$-7x - 18 = 0$$
$$-7x = 18$$
$$x = -\frac{18}{7}$$
$$x = -2\frac{4}{7}$$
Ответ: $$x = -2\frac{4}{7}$$.