Максим6 лет назад
(2х + 3) * (3х + 1) = 11х + 30;
2х * 3х + 2х * 1 + 3 * 3х + 3 * 1 = 11х + 30;
6х^2 + 2х + 9х + 3 = 11х + 30;
6х^2 + 2х + 9х - 11х + 3 - 30 = 0;
6х^2 + 11х - 11х - 27 = 0;
6х^2 - 27 = 0;
6х^2 = 27;
х^2 = 27 : 6;
х^2 = (9 * 3)/(3 * 2);
х^2 = 9/2;
х = ±√9/2;
х1 = 3/√2;
х2 = -3/√2;
х1 = (3 * √2)/(√2 * √2);
х2 = (-3 * √2)/(√2 * √2);
х1 = 3√2/2;
х2 = -3√2/2.
Ответ: х1 = 3√2/2, х2 = -3√2/2.
Проверка:
(2 * 3√2/2 + 3) * (3 * 3√2/2 + 1) = 11 * 3√2/2 + 30;
(3√2 + 3) * (9√2/2 + 1) = 33√2/2 + 30;
27 * 2/2 + 3√2 + 27√2/2 + 3 - 33√2/2 - 30 = 0;
27 + 3√2 + 13,5√2 + 3 - 16,5√2 - 30 = 0;
30 - 30 + 16,5√2 - 16,5√2 = 0;
0 = 0.