(1) 最小公倍数は(x−1)AB(x - 1)AB(x−1)AB (2) x4−2x2+1=(x2−1)2=(x−1)2(x+1)2x^4 - 2x^2 + 1 = (x^2 - 1)^2 = (x - 1)^2(x + 1)^2x4−2x2+1=(x2−1)2=(x−1)2(x+1)2 最大公約数が x−1x-1x−1 より x−1と(x−1)2(x+1)2x - 1 \quad \text{と} \quad (x - 1)^2(x + 1)^2x−1と(x−1)2(x+1)2 または (x−1)(x+1)2と(x−1)2(x - 1)(x + 1)^2 \quad \text{と} \quad (x - 1)^2(x−1)(x+1)2と(x−1)2