Ako su xxx, yyy, zzz i www pozitivni realni brojevi takvi da vrijedi
xy+z+w+yz+w+x+zw+x+y+wx+y+z=1,\frac{x}{y + z + w} + \frac{y}{z + w + x} + \frac{z}{w + x + y} + \frac{w}{x + y + z} = 1,y+z+wx+z+w+xy+w+x+yz+x+y+zw=1,
odredi
x2y+z+w+y2z+w+x+z2w+x+y+w2x+y+z.\frac{x^2}{y + z + w} + \frac{y^2}{z + w + x} + \frac{z^2}{w + x + y} + \frac{w^2}{x + y + z}.y+z+wx2+z+w+xy2+w+x+yz2+x+y+zw2.