Se consideră polinomul [tex] x^{3} + x^{2} + 4x + 4 [/tex]
Demonstrati ca
 [tex] \frac{1}{ x_{1} } + \frac{1}{ x_{2} } + \frac{1}{ x_{3} } + \frac{1}{ x_{1} x_{2} } + \frac{1}{ x_{1} x_{3} } + \frac{1}{ x_{2} x_{3} } [/tex] = - [tex] \frac{3}{4} [/tex]