4. Решите уравнение: (2x - 7)(x + 1) + 3(4x - 1)(4x + 1) = 2(5x - 2)² - 53.

$$(2x - 7)(x + 1) + 3(4x - 1)(4x + 1) = 2(5x - 2)^2 - 53$$ $$2x^2 + 2x - 7x - 7 + 3(16x^2 - 1) = 2(25x^2 - 20x + 4) - 53$$ $$2x^2 - 5x - 7 + 48x^2 - 3 = 50x^2 - 40x + 8 - 53$$ $$50x^2 - 5x - 10 = 50x^2 - 40x - 45$$ $$50x^2 - 5x - 50x^2 + 40x = -45 + 10$$ $$35x = -35$$ $$x = -1$$ **Ответ:** $$x = -1$$