Question

Resolva a Equação
(X+1) (x-1)=2 (x+7)

2x (x-1)=3

Answer 1

(x + 1) (x - 1) = 2(x + 7)
x² - x + x - 1 = 2x + 14
x² - 1 = 2x + 14
x² - 2x - 14 - 1 = 0
x² - 2x - 15 = 0

Δ = b2 - 4.a.c 
Δ = -22 - 4 . 1 . -15 
Δ = 4 - 4. 1 . -15 
Δ = 64

Há 2 raízes reais.

x = (-b +- √Δ)/2a

x' = (--2 + √64)/2.1   
x'' = (--2 - √64)/2.1

x' = 10 / 2   
x'' = -6 / 2

x' = 5   
x'' = -3

S = {-3, 5}

2x(x - 1) = 3
2x² - 2x = 3
2x² - 2x - 3 = 0

Δ = b2 - 4.a.c 
Δ = -22 - 4 . 2 . -3 
Δ = 4 - 4. 2 . -3 
Δ = 28

Há 2 raízes reais.

x = (-b +- √Δ)/2a

x' = (--2 + √28)/2.2  
x'' = (--2 - √28)/2.2

x' = 7,291502622129181 / 4   
x'' = -3,2915026221291814 / 4

x' = 1,8228756555322954   
x'' = -0,8228756555322954