Question

Quanto que é (x+1) (x-2)=3 usando Bhaskara

Answer 1

(x + 1).(x - 2) = 3

Aplica distributiva

x.x - 2.x + 1.x - 1.2 = 3

x² - 2x + x - 2 = 3

x² - x - 2 - 3 = 0

x² - x - 5 = 0

Δ = b² - 4.a.c

Δ = -1² - 4 . 1 . -5

Δ = 1 - 4. 1 . -5

Δ = 21

Há 2 raízes reais.

x = (-b +- √Δ)/2a

x' = (--1 + √21)/2.1

x'' = (--1 - √21)/2.1

x' = 5,58257569495584 / 2

x'' = -3,58257569495584 / 2

x' = 2,79128784747792

x'' = -1,79128784747792

Answer 2

$(x + 1)(x - 2) = 3 \\ {x}^{2} - 2x + x - 2 = 3 \\ {x}^{2} - x - 2 - 3 = 0 \\ {x}^{2} - x - 5 = 0$

a = 1
b = -1
c = -5

∆ = (-1)² - 4.1.(-5)
∆ = 1 + 20
∆ = 21

x = [-(-1)±√21] /2
x = [1 ± 4,58] /2

x' = [1 - 4,58]/2 = -3,58/2 = -1,79

x'' = [1 + 4,58] /2 = 5,58/2 = 2,79

ps: valores aproximados