Question 6
Non-zero real numbers $a$, $b$, $c$ satisfy the equality
$$
\frac{ab}{b-c} + \frac{bc}{c-a} + \frac{ca}{a-b} = \frac{ab}{b+c} + \frac{bc}{c+a} + \frac{ca}{a+b} + 6abc.
$$
$$
\frac{ab}{b-c} + \frac{bc}{c-a} + \frac{ca}{a-b} = \frac{ab}{b+c} + \frac{bc}{c+a} + \frac{ca}{a+b} + 6abc.
$$