Question 15
Non-zero real numbers $a, b, c$ satisfy the equality
$$
\frac{ab}{b-c} + \frac{bc}{c-a} + \frac{ca}{a-b} = \frac{ab}{b+c} + \frac{bc}{c+a} + \frac{ca}{a+b} + 6abc.
$$
Find all possible values of the expression
$$
\frac{1}{(a^2 - b^2)^2} + \frac{1}{(b^2 - c^2)^2} + \frac{1}{(c^2 - a^2)^2}
$$
$$
\frac{ab}{b-c} + \frac{bc}{c-a} + \frac{ca}{a-b} = \frac{ab}{b+c} + \frac{bc}{c+a} + \frac{ca}{a+b} + 6abc.
$$
Find all possible values of the expression
$$
\frac{1}{(a^2 - b^2)^2} + \frac{1}{(b^2 - c^2)^2} + \frac{1}{(c^2 - a^2)^2}
$$