Решите уравнение: (7.2-х) * (2 х+4) = 0 3x²=0

1) (7.2 - х) * (2 * х + 4) = 0;

Найдем корни.

7.2 * 2 * x + 7.2 * 4 - 2 * x * x - 4 * x = 0;

14.4 * x + 28.8 - 2 * x² - 4 * x = 0;

-2 * x² - 4 * x + 14.4 * x + 28.8 = 0;

-2 * x² + 10.4 * x + 28.8 = 0;

-x² + 5.2 * x + 14.4 = 0;

x² - 5.2 * x - 14.4 = 0;

Найдем дискриминант.

D = b² - 4 * a * c = (-5.2) ² - 4 * 1 * (-14.4) = 5.2² + 4 * 14.4 = 27.04 + 57.06 = 84.64 = 9.2²;

x1 = (5.2 + 9.2) / 2 = 14.4/2 = 7.2;

x2 = (5.2 - 9.2) / 2 = - 4/2 = - 2;

Ответ: х = - 2 и х = 7,2.

2) 3 * x² = 0;

x² = 0/3;

x² = 0;

x = 0;

Ответ: х = 0.