若n2+n-1=0,则n3+2n2+2008=_.
问题描述:
若n2+n-1=0,则n3+2n2+2008=___.
答
∵n2+n-1=0,
∴n3+2n2+2008
=n(n2+n-1)+(n2+n-1)+2009
=0+0+2009
=2009.
故答案为:2009.