(6x-1)(2x-1)(3x-1)(x-1)+x²= [(6x-1)(x-1)][(2x-1)(3x-1)] + x² = (6x²-7x+1)(6x²-5x+1) + x² 设6x²-6x+1=a原式=(a+x)(a-x)+x²=a²-x²+x²=a²=(6x²-6x+1)²
