题目先化简,再求值:(x+3x2−x−xx2−2x+1)÷2x−3x(\frac{x+3}{x^2-x}-\frac{x}{x^2-2x+1})÷\frac{2x-3}{x}(x2−xx+3−x2−2x+1x)÷x2x−3,其中xxx满足x2−2x−4=0x^{2}-2x-4=0x2−2x−4=0.知识点：分式的化简求值章节：未标注
