63
LCD(7, 9, 2) = 126.
LCD(7,9,13) = 7*9*13 which is 819
63
63
315
126
It is: 63
126
If you meant LCD, the answer is LCD(9, 7, 18) = 126 But if you did mean LDC, then apologies. I have no idea what that LDC is in a mathematical context.
504
63
The LCD (Lowest Common Denominator) of 7 and 9 is 63.