It is any multiple of 75.
It is 75.
The greatest common denominator, like the greatest common multiple, is infinite.
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.
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 lowest common denominator is 75 13/15 = 65/75 22/25 = 66/75 so 22/25 is bigger
LCD(75, 275) = 825
9 over 15. You divide them both by a common denominator in this case 5.