Question

先化简，再求值（要过程)

x²-2x/x²-1÷(x-1-2x-1/x+1),其中x=1/2

Answer 1

=x(x-2)/(x+1)(x-1)÷[(x+1)/(x-1)(x+1)-(2x-1)(x-1)/(x+1)(x-1)]
=x(x-2)/(x+1)(x-1)÷[(4x-2x²)/(x-1)(x+1)]
=x(x-2)/(x+1)(x-1)×(x+1)(x-1)/2x(2-x)
=x(x-2)/2x(2-x)
=(x-2)/2(2-x)
=-1/2