You can put this solution on YOUR website! Since denominators 7,9, and 11 have no common factors
other than 1, we multiply them together:
LCM = 71 = 693
LCM is "Least Common Multiple".
It is defined for the sets of INTEGER numbers only.
It is NOT DEFINED for rational numbers.
Probably, you meant LCD, which is Least Common Denominator.
Then the solution by Edwin works.