已知m^2-3m-1=0 求m^3-m^2-7m+2008的值
问题描述：
已知m^2-3m-1=0 求m^3-m^2-7m+2008的值
答
m^2-3m-1=0
m²=3m+1
m^3-m^2-7m+2008
=m²(m-1)-7m+2008
=(3m+1)(m-1)-7m+2008
=3m²-9m+2007
=3(3m+1)-9m+2007
=3+2007
=2010