Answer will be 53

Formula ab = (a+b)(b-a)

If 40 * 14 = 11, 30 * 13 = 12, 20 * 12 = 6 then 10 * 11 = ??

If;

1 + 9 + 11 = 1 &

12 + 11 + 9 = 1

Then;

14 + 11 + 9 = ?