若代数式（2mx^2+3x+1)-(3x^2-4y^2+3x)+x^2中不含x^2项,求2m^3-[3m^2-(4m+5

(2mx^2+3x+1)-(3x^2-4y^2+3x)+x^2
=2mx^2+3x+1-3x^2+4y^2-3x+x^2
=(2m-2)x^2+4y^2+1
因为不含x^2项
所以x^2项的系数必为0
即：2m-2=0,m=1
2m^3-[3m^2-(4m+5)+m]
=2m^3-3m^2+4m+5-m
=2m^3-3m^2+3m+5
代入m=1
原式=2-3+3+5=7