Question 402012
{{{k  = 3 = (4ac - b^2)/(4a) = (4*13*c - b^2)/52}}}

==> {{{156 = 52 c - b^2}}}

{{{h = 6 = -b/(2a) = -b/26}}}
==> 156 = -b ==> b = -156.

==> {{{156 = 52c - (-156)^2}}}
==> 3 = c - 468 
==> c = 471.