Question

Ajutor va rog frumosss.....intrebarea este pe foto

Answer 1

$- 2 {x}^{2} - x + 10 = 0$

$a = - 2$

$b = - 1$

$c = 10$

$\Delta = {b}^{2} - 4ac$

$\Delta = {( - 1)}^{2} - 4 \times ( - 2) \times 10$

$\Delta = 1 + 80$

$\Delta = 81 > 0 = > \exists \: x_{1} \: \neq \: x_{2}\in\mathbb{R}$

$x_{1,2}=\frac{-b\pm\sqrt{\Delta}}{2a}$

$x_{1,2}=\frac{-( - 1)\pm\sqrt{81}}{2 \times ( - 2)}$

$x_{1,2}=\frac{1\pm9}{ - 4}$

$x_{1}=\frac{1 +9}{ - 4}$

$x_{1}=\frac{10}{ - 4}$

$x_{1}= - \frac{10}{4}$

$x_{1}= - \frac{5}{2}$

$x_{2}= \frac{1 - 9}{ - 4}$

$x_{2}= \frac{ - 8}{ - 4}$

$x_{2}= 2$

$= >A\cap[ \sqrt{3} ,3] = x_{2} = 2$