Question

先化简，再求值：1-x/x+2·x²-4/x²-2x+1÷1/x²-1

其中x²-x=0

Answer 1

=1-1+2x^2-4/x^2-2x+1/x^2-1
=2x^2-4/x^2-2x+1/x^2-1
=2x^4-2x^3-4
=2x^2(x^2-x)-4
=0-4
=-4