Question

Calcule as raízes de x² – 4x – 5 = 0

Answer 1

Resposta:

$$\begin{lgathered}x^2-4x-5=0 \\ \\ \Delta=(-4)^2-4.1.(-5)=16+20=36 \\ \\ x=\frac{4+-\sqrt{36}}{2}=\frac{4+-6}{2} \\ \\ x_1=\frac{4-6}{2}=-1 \\ \\ x_2=\frac{4+6}{2}=5\end{lgathered}$$

Answer 2

Resposta:

s = {5, 1}

Explicação passo-a-passo:

$d = {b}^{2} - 4ac \\ d = {( - 4)}^{2} - 4 \times 1 \times ( - 5) \\ d = 16 + 20 \\ d = 36$

$x = \frac{ - b \frac{ + }{ - } \sqrt{d} }{2a} \\ x = \frac{ - ( - 4) \frac{ + }{ - } \sqrt{36} }{2 \times 1} \\ x = \frac{4 \frac{ + }{ - } 6}{2} \\ \\ {x}^{1} = \frac{4 + 6}{2} = \frac{10}{2} = 5 \\ {x}^{2} = \frac{4 - 6}{2} = \frac{2}{2} = 1$