Question

X² - 5x + 6 = 0
X² - 8x + 12=0
X² - 2x - 8 = 0
Não consigo fazer essas contas

Answer 1

x² - 5x + 6 = 0     a) 1    b) -5  c) 6
Δ = b² - 4 . a . c
Δ = - 5² - 4 . 1 . 6
Δ = 25 - 24
Δ = 1

- b +/- √Δ / 2 . a
- ( - 5 ) +/- √1 / 2 . 1
5 +/- 1 / 2
x' = 5+ 1 /2 = 6/2 = 3
x'' = 5 - 1 / 2 = 4/2 = 2
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x² - 8x + 12= 0     a) 1   b) - 8    c) 12
Δ = b² - 4 . a . c
Δ = - 8² - 4 . 1 . 12
Δ = 64 - 48
Δ = 16

- b +/- √Δ / 2 . a
 - ( - 8 ) +/- √16 / 2 . 1
8 +/- 4 / 2
x' = 8 + 4 / 2 = 12/2 = 6
x'' = 8 - 4 / 2 = 4/2 = 2

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x² - 2x - 8 = 0           a) 1    b ) - 2    c) - 8
Δ =  b² - 4 . a . c
Δ = - 2² - 4 . 1 . - 8
Δ = 4 +32
Δ = 36

- b +/- √Δ / 2 . a
- ( - 2 ) +/- √36 / 2 . 1
2 +/- 6 / 2
x' = 2 + 6 / 2 = 8/2 = 4
x'' = 2 - 6 / 2 = - 4 /2 = - 2