Question

Encontre as raízes das seguintes equações do 2° Grau:

x² −3x −4 = 0​

Answer 1

Resposta:

A = (-3)² - 4(1)(-4)

A= 9 +16=25

x= 3 + - 5/2(1)

x= 8/2=4

x= -2/2 = -1

S=(-1 ; 4)

Answer 2

$\Large\mathsf\displaystyle{} {x}^{2} - 3x - 4 = 0 \\ \\ \Large\mathsf\displaystyle{}\begin{cases}a = 1 \\ b = - 3 \\ c = - 4\end{cases} \\\\\Large\mathsf\displaystyle{}x = \dfrac{ - \left( - 3\right) \pm \sqrt{\left( - 3\right)^{2} - 4\cdot1\cdot\left( - 4\right)} }{2\cdot1} \\\\\\\Large\mathsf\displaystyle{}x = \dfrac{3 \pm \sqrt{9 + 16} }{2} \\\\\\ \Large\mathsf\displaystyle{}x = \dfrac{3 \pm \sqrt{25} }{2} \\\\ \\ \Large\mathsf\displaystyle{}x = \frac{3 \pm5}{2} \\\\ \\ \Large\mathsf\displaystyle{}x = \dfrac{3 + 5}{2} \\ \\ \\ \Large\mathsf\displaystyle{}x = \dfrac{3 - 5}{2}$

Solução:

$\Large\displaystyle\text{ \begin{gathered} \underline{\boxed{\boldsymbol{ x_{1} = 4 }}}\end{gathered} }$

$\Large\displaystyle\text{ \begin{gathered} \underline{\boxed{\boldsymbol{ x_{2} = - 1 }}}\end{gathered} }$

$\displaystyle\text{ \begin{gathered} \underline{\boxed{\boldsymbol{{ \red{Bons}} \blue{\:Estudos}}}}\end{gathered} }$