若m²-m-2=0则代数式m³-3m+5=

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若m²-m-2=0则代数式m³-3m+5=若m²-m-2=0则代数式m³-3m+5=若m²-m-2=0则代数式m³-3m+5=m²

若m²-m-2=0则代数式m³-3m+5=
若m²-m-2=0则代数式m³-3m+5=

若m²-m-2=0则代数式m³-3m+5=
m²-m-2=0
所以:m²-m=2
m³-3m+5
=m³-m²+m²-3m+5
=m(m²-m)+m²-3m+5
=2m+m²-3m+5
=m²-m+5
=2+5
=7

m²-m-2=0
m²-m=2
m³-3m+5
=m(m²-m)+m²-3m+5
=2m+m²-3m+5
=m²-m+5
=2+5
=7

因为m²-m-2=0
所以m³-m²-2m=0
所以m³=m²+2m
所以m³-3m+5=m²-m+5=7