Duas raízes reais e diferentes.
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x² - 2x - 3 = 0
∆ = b² - 4ac
∆ = (-2)² - 4 × 1 × (-3)
∆ = 4 + 12
∆ = 16
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[tex] \frac{ 2 + \sqrt{16} }{2} = \frac{2 + 4}{2} \\ \frac{8}{2} = 4[/tex]
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[tex] \frac{2 - \sqrt{16} }{2} = \frac{2 - 4}{2} \\ \frac{ - 2}{2} = - 1[/tex]
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S = {x' = 4 ; x" = -1}
