Question

Equacao 2 grau x2+5×+4=0

Answer 1

• x² + 5x + 4 = 0

a = 1

b = 5

c = 4

∆ = b² - 4 . a . c

∆ = 5² - 4 . 1 . 4

∆ = 25 - 4 . 1 . 4

∆ = 25 - 16

∆ = 9

x = - b ± √∆

________

2 . a

x = - 5 ± 3

________

2

x' = - 5 + 3

________

2

x' = - 1

x" = - 5 - 3

______

2

x" = - 4

Answer 2

$\large\boxed{\begin{array}{lr}x {}^{2} + 5x + 4 = 0 \\ \\ a = 1 \\ b = 5 \\ c = 4 \\ \\ ∆ = {b}^{2} - 4.a.c \\ ∆ = 5 {}^{2} - 4.1.4 \\ ∆ = 25 - 16 \\ ∆ = 9 \\ \\ x = \frac{ - b \pm \sqrt{∆} }{2.a} \\ \\ x = \frac{ - 5 \pm \sqrt{9} }{2.1} \\ \\ x = \frac{ - 5 \pm3}{2} \begin{cases} x_{1} = \frac{ - 5 + 3}{2} = \frac{ - 2}{2} = \boxed{ - 1} \\ \\ x_{2} = \frac{ - 5 - 3}{2} = \frac{ - 8}{2} = \boxed{ - 4} \end{cases} \\ \\ \boxed{s =[-1,-4] } \end{array}}$