若n2+n-1=0，则n3+2n2+2008=

网友回答

∵n2+n-1=0，
∴n3+2n2+2008
=n（n2+n-1）+（n2+n-1）+2009
=0+0+2009
=2009．
故答案为：2009．
======以下答案可供参考======
供参考答案1:
这个容易的很，你把后边的式子拆成 n^3+n^2+n^2+2008=n(n^2+n)+n^2+2008=n+n^2+2008=2009
供参考答案2:
N^2+N=1有N^3+N^2=N所以
N^3+2N^2+2008
=(N^3+N^2)+N^2+2008
=N+N^2+2008
=2009供参考答案3:
n^3+2*n^2+2008
=(n^3+n^2-n)+(n^2+n-1)+2009
=n*(n^2+n-1)+(n^2+n-1)+2009
=0+0+2009
=2009