(x+y+z)^2-(x^2+y^2+z^2)=2(xy+yz+zx)
所以xy+yz+zx=(3^2-29)/2=-10
(x+y+z)(x^2+y^2+z^2)
=x^3+y^3+z^3+xy^2+xz^2+yx^2+yz^2+zx^2+zy^2
=x^3+y^3+z^3+xy(x+y)+yz(y+z)+zx(z+x)
=x^3+y^3+z^3+xy(3-z)+yz(3-x)+zx(3-y)
=x^3+y^3+z^3+3(xy+yz+zx)-3xyz
所以xyz=(45+3*(-10)-3*29)/3=-24