No, they are factors.
The only Least Common Multiple (LCM) for 7 9 14 is 126.
It is: 126
The least common multiple of 42 and 126 is 126.
126
No, they are factors.
The lists of factors of 126 and multiples of 12 do not have any numbers in common.
The Least Common Multiple (LCM) for 18 42 is 126.
The least common multiple of the numbers 126 and 140 is 1,260.
You can have three common multiples, but only one can be least and that's 126. Others include 252 and 378.
Any pair of numbers has an infinite set of common multiples. The lowest common multiple of 9 and 21 is 63 and the others are multiples of this, e.g. 63, 126, 189, 252, 315, ...
The least common multiple of the numbers 7 and 18 is 126.
You need at least two denominators to find something in common between them.