Matemática, perguntado por diogo0921sombra, 3 meses atrás


  {x }^{2}  - 3x - 18 = 0
qual o valor desse número? ​

Soluções para a tarefa

Respondido por attard
2

\Large\mathsf\displaystyle{} {x}^{2}  - 3x - 18 = 0 \\\\\Large\mathsf\displaystyle{} \begin{cases}a = 1 \\ b =  - 3 \\ c =  - 18\end{cases} \\\\ \Large\mathsf\displaystyle{}x =  \dfrac{ -\left( - 3\right) \pm \sqrt{\left( - 3\right)^{2}  - 4\cdot1\cdot\left( - 18\right)}  }{2\cdot1}  \\\\\Large\mathsf\displaystyle{}x =  \dfrac{3 \pm \sqrt{9 + 72} }{2} \\\\\Large\mathsf\displaystyle{}x =  \dfrac{3 \pm \sqrt{81} }{2} \\\\\\ \Large\mathsf\displaystyle{}x =  \dfrac{3 \pm9}{2} \\\\\Large\mathsf\displaystyle{}x =  \dfrac{3 + 9}{2}    \\\\\Large\mathsf\displaystyle{}x =  \dfrac{3 - 9}{2} \\\\\\\Large\mathsf\displaystyle{} x =   6 \\ \Large\mathsf\displaystyle{}x =  - 3

Solução:

\Large\displaystyle\text{$\begin{gathered} \underline{\boxed{\boldsymbol{  x_{1} =  - 3 }}}\end{gathered}$}

\Large\displaystyle\text{$\begin{gathered} \underline{\boxed{\boldsymbol{  x_{2} = 6  }}}\end{gathered}$}

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

Anexos:

diogo0921sombra: obrigado meu amigo
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