Question 458365
{{{2x^2 + 2px = q^2}}} is equivalent to {{{x^2 + px - q^2/2 = 0}}}

==> The sum of the roots are p + q = -p, or 2p = q.

Now p - q = 6 ==> p - 2p = 6, or p = -6.

==> q = 2*-6 = -12, so that pq = -6*-12 = 72.