Răspuns:
-0,8.
Explicație pas cu pas:
Avem ecuatia x²-2x-5=0. La ea se aplica Relatiile Viete
[tex]\left \{ {{x_{1}+x_{2}=2} \atop {x_{1}x_{2}=-5}} \right. ~acum~calculam~valoarea\\\frac{2x_{1}+2x_{2}}{x_{1}x_{2}} =\frac{2(x_{1}+x_{2})}{x_{1}x_{2}} =\frac{2*2}{-5}=-\frac{4}{5}=-0,8.[/tex]
[tex]\it x^2-2x-5=0 \stackrel{R. Vi\grave{e}te}{\Longrightarrow} \begin{cases}\it x_1+x_2=2\\ \\ \it x_1x_2=-5\end{cases}\\ \\ \\ \dfrac{2x_1+2x_2}{x_1x_2}=\dfrac{2(x_1+x_2)}{x_1x_2}=\dfrac{2\cdot2}{-5}=-\dfrac{4}{5}[/tex]
