因为x=2005
所以|5x^2-4x+9|=5x^2-4x+9
5|x^2-x+1|=5x^2-5x+5
所以
|5x^2-4x+9|-5|x^2-x+1|-2x+2006
=5x^2-4x+9-5x^2+5x-5-2x+2006
=-x+2010
=-2005+2010
=5