(x² - 5x)² - 30x(x - 5) - 216 = 0
[x(x - 5)]² - 30[x(x - 5)] - 216 = 0
Сделаем замену :
x(x - 5) = m
m² - 30m - 216 = 0
D = (- 30)² - 4 * (- 216) = 900 + 864 = 1764 = 42²
(x² - 5x)² - 30x(x - 5) - 216 = 0
[x(x - 5)]² - 30[x(x - 5)] - 216 = 0
Сделаем замену :
x(x - 5) = m
m² - 30m - 216 = 0
D = (- 30)² - 4 * (- 216) = 900 + 864 = 1764 = 42²