若m²+m-1=0,则m³+2m²+3的值为___.

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若m²+m-1=0,则m³+2m²+3的值为___.

m²+m-1=0 m²+m=0
m³+2m²+3
=m(m²+2m)+3
=m(m²+m+m)+3
=m(1+m)+3
=m+m²+3
=1+3
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