题目先化简,再求值:(x+1)(x−1)+(2x−1)2−2x(2x−1)\left(x+1\right)\left(x-1\right)+\left(2x-1\right)^{2}-2x\left(2x-1\right)(x+1)(x−1)+(2x−1)2−2x(2x−1),其中x=3x=\sqrt{3}x=3.知识点：平方差公式章节：数与式 / 整式
