(X平方-2X)的平方-7(X平方-2X)+12
=(x²-2x-3)(x²-2x-4)
=(x-3)(x+1)(x²-2x+1-5)
=(x-3)(x+1)[(x-1)²-5]
=(x-3)(x+1)(x-1+√5)(x-1-√5)