Question

Encontre o valor de f(x) = x²– 5x + 6 para que f(x) = 2

a) x1 = 2 e x2 = – 5
b) x1 = 5 e x2 = - 2
c) x1 = -9 e x2 = - 2
d)x1 = 4 e x2 = 1

Answer 1

f(x) = x² - 5x + 6

f(x) = 2

x² - 5x + 6 = 2

x² - 5x + 6 - 2

x² - 5x + 4 = 0

∆ = b² - 4 . a . c

∆ = (-5)² - 4 . 1 . 4

∆ = 25 - 16

∆ = 9

x = - b ± √∆

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2a

x' = -(-5) + 3

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2 . 1

x' = 5 + 3

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2

x' = 8

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2

x' = 4

x" = -(-5) - 3

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2 . 1

x" = 5 - 3

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2

x" = 2

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2

x" = 1

S = {4 , 1}

Letra D