735.2) 20 + 8x – x² = 0; 4) (x + 5)(x – 3) = 2x – 7;

Решим уравнения.

1. $$20 + 8x - x^2 = 0$$
   $$-x^2 + 8x + 20 = 0$$
   $$x^2 - 8x - 20 = 0$$
   По теореме Виета:
   $$x_1 + x_2 = 8$$
   $$x_1 \cdot x_2 = -20$$
   $$x_1 = 10$$
   $$x_2 = -2$$

   Ответ: x₁ = 10, x₂ = -2

2. $$(x + 5)(x - 3) = 2x - 7$$
   $$x^2 - 3x + 5x - 15 = 2x - 7$$
   $$x^2 + 2x - 15 = 2x - 7$$
   $$x^2 + 2x - 2x - 15 + 7 = 0$$
   $$x^2 - 8 = 0$$
   $$x^2 = 8$$
   $$x_1 = \sqrt{8} = 2\sqrt{2}$$
   $$x_2 = -\sqrt{8} = -2\sqrt{2}$$

   Ответ: x₁ = $$2\sqrt{2}$$, x₂ = $$-2\sqrt{2}$$