Question

若m的平方+m-1=0,求m的3次方+2m的平方+2007的值

Answer 1

因为m^2+m-1=0

所以m^2=1-m

-m^2-m=-1

m的3次方+2m的平方+2007

=m^2(m+2)+2007

=(1-m)(m+2)+2007

=-m^2-m+2+2007

=-1+2009

=2008