The roots of polynomial $ p(a) $ are:
$$ \begin{aligned}a_1 &= \frac{ 1 }{ 3 }\\[1 em]a_2 &= -\frac{ 3 }{ 5 } \end{aligned} $$The solutions of $ 15a^2+4a-3 = 0 $ are: $ a = -\dfrac{ 3 }{ 5 } ~ \text{and} ~ a = \dfrac{ 1 }{ 3 }$.
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