4y²-4y/y²-2y+1÷(y+1/y-1-y-1/y+1)÷(3y+3)

4y²-4y/y²-2y+1÷(y+1/y-1-y-1/y+1)÷(3y+3)
4y²-4y/y²-2y+1÷(y+1/y-1-y-1/y+1)÷(3y+3)

4y²-4y/y²-2y+1÷(y+1/y-1-y-1/y+1)÷(3y+3)
4y²-4y/y²-2y+1÷(y+1/y-1-y-1/y+1)÷(3y+3)
=4y(y-1)/y(y-2)÷【（y+1）²-（y-1）²】/（y+1）(y-1)÷3（y+1）
=4（y-1）²/3（y-2）÷4y
=（y-1）²/3y（y-2）
如果本题有什么不明白可以追问,