12c2 + 12dc2 = 324 ---> x 9 ---> 108c2 + 108dc2 = 2916
6c2 + 9dc2 = 204 ---> x -12 ---> -72c2 - 108dc2 = -2448
Add down the columns: 36c2 = 468
Divide by 36: c2 = 13 ---> c = ±√13
12c2 + 12dc2 = 324 ---> 12(13) + 12d(13) = 324
---> 156 + 156d = 324
---> 156d = 168 ---> d = 168/156 = 14/13
12c2 + 12dc2 = 324 ---> x 9 ---> 108c2 + 108dc2 = 2916
6c2 + 9dc2 = 204 ---> x -12 ---> -72c2 - 108dc2 = -2448
Add down the columns: 36c2 = 468
Divide by 36: c2 = 13 ---> c = ±√13
12c2 + 12dc2 = 324 ---> 12(13) + 12d(13) = 324
---> 156 + 156d = 324
---> 156d = 168 ---> d = 168/156 = 14/13