x^2-x-1=0,所以x^2-x = 1
-x^3+2x^2+2011
= -x^3 + x^2 + x^2 + 2011
= -x(x^2 - x) + x^2 + 2011
= -x + x^2 + 2011
= 1 + 2011
=2012