a) $$(2x - 5)(5x + 4) - 10x^2 = 14$$
$$10x^2 + 8x - 25x - 20 - 10x^2 = 14$$
$$-17x - 20 = 14$$
$$-17x = 34$$
$$x = -2$$
б) $$(4y + 3)(3y + 1) = (2y - 1)(6y + 5) - 1$$
$$12y^2 + 4y + 9y + 3 = 12y^2 + 10y - 6y - 5 - 1$$
$$12y^2 + 13y + 3 = 12y^2 + 4y - 6$$
$$13y - 4y = -6 - 3$$
$$9y = -9$$
$$y = -1$$
**Ответы:**
a) $$\mathbf{x = -2}$$
б) $$\mathbf{y = -1}$$