1.已知A=一2xy²,B=一1/4x³+x²y-3xy²-1/6y³,求A³B.2.设m²+2m+1=0,求m³+2m²+2008的值.3.梯形的上底长为(4n+m)厘米,下底长为(2m+5n)厘米,高为(9n+3m)厘米,求此梯形的面积.

1.已知A=一2xy²,B=一1/4x³+x²y-3xy²-1/6y³,求A³B.2.设m²+2m+1=0,求m³+2m²+2008的值.3.梯形的上底长为(4n+m)厘米,下底长为(2m+5n)厘米,高为(9n+3m)厘米,求此梯形的面积.
1.已知A=一2xy²,B=一1/4x³+x²y-3xy²-1/6y³,求A³B.
2.设m²+2m+1=0,求m³+2m²+2008的值.
3.梯形的上底长为(4n+m)厘米,下底长为(2m+5n)厘米,高为(9n+3m)厘米,求此梯形的面积.

1.已知A=一2xy²,B=一1/4x³+x²y-3xy²-1/6y³,求A³B.2.设m²+2m+1=0,求m³+2m²+2008的值.3.梯形的上底长为(4n+m)厘米,下底长为(2m+5n)厘米,高为(9n+3m)厘米,求此梯形的面积.
A^3B=(-2xy^2)^3(-1/4x^3+x^2y-3xy^2-1/6y^3)
=(-8x^3y^6)(-1/4x^3+x^2y-3xy^2-1/6y^3)
=2x^6y^6-8x^5y^7+24x^4y^8+4/3x^3y^9
m^3+2m^2+2008=m^3+2m^2+m-m+2008=m(m^2+2m+1)-m+2008=2008-m
从已知条件,可以求得：m=-1
所以,所求式子的值为：2008-m=2008-(-1)=2009
根据梯形面积公式得：梯形的面积为：
1/2[(4n+m)+(2m+5n)](9n+3m)=1/2(9n+3m)^2=81/2*n^2+9/2*m^2+27nm

2、（m+1）^2=1 m=-1 m^3+2m^2+2008=2009

3、S=0.5((4n+m)*(2m+5n)*(9n+3m))