Question

Quais as raízes da equação?​

Answer 1

Resposta:

$(x + 2).(x - 4) = x + 2$

${x}^{2} - 4x + 2x - 8 = x + 2$

${x}^{2} - 2x- 8 - x - 2 = 0$

${x}^{2} - 3x - 10 = 0$

a = 1

b = - 3

c = - 10

$Δ = {b}^{2} - 4.a.c$

$Δ = {( - 3)}^{2} - 4.1.( - 10)$

$Δ = 9 + 40$

$Δ = 49$

$x = \frac{ - b \: ± \: \sqrt{Δ} }{2.a}$

$x = \frac{ - ( - 3) \: ± \: \sqrt{49} }{2.1}$

$x = \frac{ 3 \: ± \: 7 }{2}$

$x'= \frac{ 3\: + \: 7}{2}$

$x'= \frac{11}{2}$

$x" = \frac{ 3 \: - \: 7 }{2}$

$x" = \frac{ -4 }{2}$

$x" = -2$

S = { 11/2 , - 2 }