The roots of polynomial $ p(x) $ are:
$$ \begin{aligned}x_1 &= -\frac{ 2 }{ 7 }+\frac{ 2 \sqrt{ 13}}{ 7 }i\\[1 em]x_2 &= -\frac{ 2 }{ 7 }-2 \frac{\sqrt{ 13 }}{ 7 }i \end{aligned} $$The solutions of $ 7x^2+4x+8 = 0 $ are: $ x = -\dfrac{ 2 }{ 7 }+\dfrac{ 2 \sqrt{ 13}}{ 7 }i ~ \text{and} ~ x = -\dfrac{ 2 }{ 7 }-\dfrac{ 2 \sqrt{ 13}}{ 7 }i$.
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