B
m³-8m-2n²+6n+2013
=m(m²-3m+1)+3m²-9m-2n²+6n+2013
=0+3(m²-3m+1)-3-2(n²-3n+1)+2+2013
=0+0-3-0+2+2013
=2012
m、n是方程的两个根
∴m²-3m+1=0 n²-3n+1=0
∴m³-8m-2n²+6n+2013
=m(3m-1)-8m-2(3n-1)+6n+2013
=3m²-m-8m-6n+2+6n+2013
=3m²-9m+2015
=3(3m-1)-9m+2015
=9m-3-9m+2015
=2012