m,n是一元二次方程X2-3X+1=0的两个根
所以,m^2-3m+1＝0,n^2-3n+1＝0
2m^2+4n^2-6m-12n+2007
=2(m^2-3m+1)+4(n^2-3n+1)+2001
=2×0＋4×0＋2001
＝2001