x^4-2008x^2+2009x-2008
=(x^4+x)-2008x^2+2008x-2008
=x(x+1)(x^2-x+1)-2008(x^2-x+1)
=(x^2-x+1)(x^2+x-2008)=0
x^2-x+1无解,
x^2+x-2008=0
x=(-1±√8033)/2