It is 75.
A common denominator is 75.
There is no such thing as a most common denominator.
A common denominator, though not the least, is 7500.
The common denominator of 15 and 9 is 45.
There is no greatest common multiple, as the multiples are infinite. Their greatest common denominator is 15. Their lowest common multiple is 7650.
The greatest common denominator, like the greatest common multiple, is infinite.
What is the lowest common denominator of 15 over 57?
LCD(75, 275) = 825
Divide the numerator and the denominator by their greatest common factor. In this fraction, that's 15.
75 (3 x 25, 15 x 5, 25 x 3)
The greatest common denominator is infinite. The least common denominator is 45.