来自董颖颖的问题
【先化简,再求值:(x−1x−x−2x+1)÷2x2−xx2+2x+1,其中x满足x2-x-1=0.】
先化简,再求值:(x−1x−x−2x+1)÷2x2−xx2+2x+1,其中x满足x2-x-1=0.


【先化简,再求值:(x−1x−x−2x+1)÷2x2−xx2+2x+1,其中x满足x2-x-1=0.】
先化简,再求值:(x−1x−x−2x+1)÷2x2−xx2+2x+1,其中x满足x2-x-1=0.
原式=(x−1)(x+1)−x(x−2)x(x+1)