根据题意得:
(6-2m)xy的系数为0
∴6-2m=0 m=3
化简:
(-m^3+2m^2+m-9)-(m^3+2m^2+m-9)
=-2m³
把m=3代入-2m³=-2×3³=-54
即 (-m^3+2m^2+m-9)-(m^3+2m^2+m-9)=54
多项式5x^2-2mxy-3y^2与多项式6xy-9x+5的和中不含xy项,求代数式(-m^3+2m^2+m-9)-(m^3+2m^2+m-9)的值!
多项式5x^2-2mxy-3y^2与多项式6xy-9x+5的和中不含xy项,求代数式(-m^3+2m^2+m-9)-(m^3+2m^2+m-9)的值!
数学人气:325 ℃时间:2019-10-19 21:17:51
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