(х - 1) (х² + х + 1) = 999;
x × x² + x × x + x × 1 + (- 1) × x² + (- 1) × x + (- 1) × 1 = 999;
x³ + x² + x + (- x²) + (- x) + (- 1) = 999;
x³ + x² + x - x² - x - 1 = 999;
x³ + (x² - x²) + (x - x) - 1 = 999;
x³ + 0 + 0 - 1 = 999;
x³ - 1 = 999;
x³ = 999 + 1;
x³ = 1 000;
x = ∛1 000;
x = ∛10³;
x = 10.
ответ: 10.
Удачи Вам! :)
(х - 1) (х² + х + 1) = 999;
x × x² + x × x + x × 1 + (- 1) × x² + (- 1) × x + (- 1) × 1 = 999;
x³ + x² + x + (- x²) + (- x) + (- 1) = 999;
x³ + x² + x - x² - x - 1 = 999;
x³ + (x² - x²) + (x - x) - 1 = 999;
x³ + 0 + 0 - 1 = 999;
x³ - 1 = 999;
x³ = 999 + 1;
x³ = 1 000;
x = ∛1 000;
x = ∛10³;
x = 10.
ответ: 10.
Удачи Вам! :)