=1-(x-1)/(x-1)²×(x-1)²/(x²-x+1)
=1-(x-1)/(x²-x+1)
=(x²-x+1-x+1)/(x²-x+1)
=(x²-2x+2)/(x²-x+1)对不起，题目是1-｛x-【1/(1-x)】｝²÷【(x²-x+1)/(-2x+1)】，谢谢1-｛x-【1/(1-x)】｝²÷【(x²-x+1)/( x² -2x+1)】=1-[x+1/(x-1)]² ×(x-1)²/(x²-x+1)=1-(x²-x+1)²/(x-1)²×(x-1)²/(x²-x+1)=1-(x²-x+1)=x-x²