俊狼猎英团队为您解答
x(x²+xy+y²)-y(x²+xy+y²)+3xy(y-x)
=X^3+X^2Y+XY^2-X^2Y-XY^2-Y^3+3XY^2-3X^2Y
=X^3-3X^2Y+3XY^2-Y^3
=(X-Y)^3
当X=1/2,Y=3时,
原式=(-1/2)^3
=-1/8
追问能再帮我这道题吗?我会加分的,
已知x+y=1/2 ,xy=1 求x^3y+2x^2y^2+xy^3的值
追答x^3y+2x^2y^2+xy^3
=XY(X^2+2XY+Y^2)
=XY(X+Y)^2
=1/2*1^2
=1/2