已知x+y+z=1,xy+yz+zx=2,xyz2,求x2(y+z)+y2(z+x)+z2(x+y)的值

x+y+z=1xy+yz+zx=21*2=(x+y+z)(xy+yz+zx)=x(xy+yz+zx)+y(xy+yz+zx)+z(xy+yz+zx)=x²y+xyz+zx²+xy²+y²z+xyz+xyz+yz²+z²x=x²(y+z)+y²(z+x)+z²(x+y)+3xyz=x²(y+z)+y&...