2x3+3x2−2x−3=(x−1)(x+1)(2x+3)2x^3 + 3x^2 - 2x - 3 = (x - 1)(x + 1)(2x + 3)2x3+3x2−2x−3=(x−1)(x+1)(2x+3) 最大公約数がx−1x - 1x−1より (x−1)(x+1)と(x−1)(2x+3)(x - 1)(x + 1) \quad \text{と} \quad (x - 1)(2x + 3)(x−1)(x+1)と(x−1)(2x+3) 書き直すと x2−1と2x2+x−3x^2 - 1 \quad \text{と} \quad 2x^2 + x - 3x2−1と2x2+x−3