(x² + 12x)² + 18(x² + 12x) + 81 = 0
Сделаем замену :
x² + 12x = m
m² + 18m + 81 = 0
(m + 9)² = 0
m + 9 = 0
m = - 9
x² + 12x = - 9
x² + 12x + 9 = 0
D = 12² - 4 * 9 = 144 - 36 = 108 = (6√3)²
(x² + 12x)² + 18(x² + 12x) + 81 = 0
Сделаем замену :
x² + 12x = m
m² + 18m + 81 = 0
(m + 9)² = 0
m + 9 = 0
m = - 9
x² + 12x = - 9
x² + 12x + 9 = 0
D = 12² - 4 * 9 = 144 - 36 = 108 = (6√3)²