原式为:m²(m+4)+2m(m²-1)-3m³
=m³+4m²+2m³-2m-3m³
=4m²-2m
=2m(2m-1)
再将m=2/5代入,有
原式=2m(2m-1)
=2×2/5(2×2/5-1)
=﹣4/25
化简求值m^2(m+4)+2m(m^2 -1)-3m^3,其中m=2/5
化简求值m^2(m+4)+2m(m^2 -1)-3m^3,其中m=2/5
数学人气:550 ℃时间:2020-02-04 03:29:10
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