Question

$5 { \times }^{2} + 21 \times + 4 = 0$
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Answer 1

Resposta:

Substituindo para encontrar as raízes reais:

$x_{1} = \frac{-21+\sqrt{21^{2}-4*5*4 } }{2*5} =>x_{1} =\frac{-2}{10} =>x_{1} =-\frac{1}{5}$

$x_{2} = \frac{-21-\sqrt{21^{2}-4*5*4 } }{2*5} =>x_{2} =\frac{-40}{10} =>x_{2} =-4$