若m^3+2m-1=3,则4m^3+8m-7=

若m^3+2m-1=3,则4m^3+8m-7=
若m^3+2m-1=3,则4m^3+8m-7=

若m^3+2m-1=3,则4m^3+8m-7=
因为m³+2m-1=3
所以m³+2m=4
4m³+8m-7
=(4m³+8m)-7
=4(m³+2m)-7 把m³+2m=4代入
=4×4-7
=16-7
=9