下列方程:①3x^2+1=0 ②根号2x^2-根号3x+1=0

1①,②都是
故选B
2 由题知
m^2-2m-1=0
n^2-2n-1=0
且m+n=-b/a=2
mn=-1
即m^2-2m=1
n^2-2n=1
即3m^2-n^2-8m+1
=3m^2-6m-n^2-2m+1
=3(m^2-2m)-n^2-2m+1
=3-n^2-2m+1
=-n^2-2m+4
=-n^2+2n-2n-2m+4
=-（n^2-2n）-2（m+n）+4
=-1-2×2+4
=-1