若m²+m-1=0,求m³+2m²+2008的值
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若m²+m-1=0,求m³+2m²+2008的值
若m²+m-1=0,求m³+2m²+2008的值
若m²+m-1=0,求m³+2m²+2008的值
∵m²+m-1=0
∴m²=1-m
∴m³+2m²+2008
=m(1-m)+2m²+2008
=m²+m+2008
=1+2008
=2009
误解
无解
等式两边者都乘以(m+1)
(m²+m-1)*(m+1)=0
m^3+m^2-m+m^2+m-1=0
m^3+2m^2=1
所以:m³+2m²+2008=1+2008=2009