Is this even solvable?

Algebra Level 5

Consider the following polynomial:

$x^3 + 75x -251 = 0$

If the roots of the polynomial are $a$ , $b$ and $c$ .

Find: $\left| \dfrac{2}{251} \cdot \left( \displaystyle \sum_{a, b, c} (a + b)^3 \right) \right|$