Question

3)x²+2x-8=0
4)x²-5x+8=0​

Answer 1

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3)

x² + 2x - 8 = 0

∆ = 2² - 4(1)(-8)

∆ = 4 + 32

∆ = 36

$\frac{ - 2 + - \sqrt{36} }{2} \\ \\ \frac{ - 2 + - 6}{2}$

x' = 4/2 → 2

x" = -8/2 → -4

S = { 2 ; -4 }

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4)

x² - 5x + 8 = 0

∆ = (-5)² - 4(1)(8)

∆ = 25 - 32

∆ = -7

∆ < 0, Não possui raízes reais

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Att: MarcosPCV