因为 x² - 3 = 0
所以 x² = 3
x(x + 1)² - x(x² + x) - x - 9
= x(x + 1)(x + 1) - x²(x + 1) - x - 9
= x(x + 1) - x - 9
= x² - 9
= 3 -9
= -6
因为 x² - 3 = 0
所以 x² = 3
x(x + 1)² - x(x² + x) - x - 9
= x(x + 1)(x + 1) - x²(x + 1) - x - 9
= x(x + 1) - x - 9
= x² - 9
= 3 -9
= -6