Question

x²+3X-10=0
(reposta errada = denunciado )​

Answer 1

Resposta:

$\sf \displaystyle x^{2} + 3x - 10 = 0$

$\sf \displaystyle ax^{2} + bx + c = 0$

a = 1

b = 3

c = - 10

Determinar o Δ:

$\sf \displaystyle \Delta = b^2 -\:4ac$

$\sf \displaystyle \Delta = 3^2 -\:4 \cdot 1 \cdot (- 10)$

$\sf \displaystyle \Delta = 9 + 40$

$\sf \displaystyle \Delta = 49$

Determinar a raízes da equação:

$\sf \displaystyle x = \dfrac{-\,b \pm \sqrt{ \Delta } }{2a} = \dfrac{-\,3 \pm \sqrt{ 49} }{2 \cdot 1 } = \dfrac{-\,3 \pm 7} {2} \Rightarrow\begin{cases} \sf x_1 = &\sf \dfrac{-\,3 + 7}{2} = \dfrac{4}{2} = 2 \\\\ \sf x_2 = &\sf \dfrac{-\,3 - 7}{2} = \dfrac{- 10}{2} = - 5\end{cases}$

$\sf \boldsymbol{ \sf \displaystyle S = \{ x \in \mathbb{R} \mid x = -\: 5 \mbox{\sf \;e } x = 2 \} }$