题目先化简,再求值:(2x−1)2−(3x+1)(3x−1)+5x(x−1)\left(2x-1\right)^{2}-\left(3x+1\right)\left(3x-1\right)+5x\left(x-1\right)(2x−1)2−(3x+1)(3x−1)+5x(x−1),其中x=19x=\frac{1}{9}x=91.知识点：单项式乘多项式章节：数与式 / 整式
