m^2+m-1=0则m^3+2m^2+3=

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m^2+m-1=0则m^3+2m^2+3=

∵m^2+m-1=0
∴m^2+m=1
则m^3+2m^2+3=m^3+m^2+m^2+3
=m(m^2+m)+m^2+3
=m+m^2+3
=1+3
=4