实际上就是因式分解:左端 = x³ - x² - x + 1 = x²(x - 1) - (x - 1) = (x - 1) (x² - 1) = (x - 1) (x - 1)(x + 1) = (x ² - 1) (x + 1)所以 x = +1 或者 x=- 1 实际中,先观察发现,当x = 1时,等式成立,所以左边的多项式必定包含有因子(x - 1)
x=-1