21.

The centre of circle lies on x + y = 3 and touching the lines x = 3, y = 3 then find diameter of circle

$\mathrm{If} \left|\begin{array}{ccc}\mathrm{x} - 2& 2\mathrm{x} - 3& 3\mathrm{x} - 4\\ 2\mathrm{x} - 3& 3\mathrm{x} - 4& 4\mathrm{x} - 5\\ 3\mathrm{x} - 5& 5\mathrm{x} - 8& 10\mathrm{x} - 17\end{array}\right| = {\mathrm{Ax}}^3 + {\mathrm{Bx}}^2 + \mathrm{Cx} + \mathrm{D} \mathrm{then} \mathrm{find} \mathrm{the} \mathrm{absolute} \mathrm{value} \mathrm{B} + \mathrm{C} = ?$