[tex] x^{3} + 3 x^{2} * \frac{1}{x} + 3x* \frac{1}{ x^{2} } + \frac{1}{ x^{3} } =64
x^{3} + 3 x } + 3* \frac{1}{ x } + \frac{1}{ x^{3} } =64[/tex]·
Dupa asta, dai factor comun pe 3 asa:
[tex] x^{3} + \frac{1}{x^{3} } + 3(x+ \frac{1}{x} )=64[/tex]
Dar tu stii ca [tex]x+ \frac{1}{x} =4[/tex]
Rezulta ca [tex] x^{3} + \frac{1}{ x^{3} } +3*4=64
x^{3} + \frac{1}{ x^{3} } +12=64
x^{3} + \frac{1}{ x^{3} } =64-12
x^{3} + \frac{1}{ x^{3} } =52[/tex]
Sper ca ai inteles.
