# Cubes and cubes

Algebra Level 4

$\large (x^{2}+x-2)^{3}+(2x^{2}-x-1)^{3}=27 (x^{2}-1)^3$

If the four distinct real roots to the equation above are $a$, $b$, $c$ and $d$, find $-(a+b+c+d)$.

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