(1,9) (3,3)
9
(42,1)(21,2)(14,3)(7,6)
The paired prime factors of 150 are: 5 x 5
(272,1)(136,2)(68,4)(34,8)(17,16)
The factors of 9 are 1, 3, and 9
3
The factors of 9 are: 1, 3, 9.
5 and 9 are factors of 45. The GCF of 5 and 45 is 5. The LCM of 5 and 45 is 45.
Every number except zero is a factor of every other number. Usually this kind of question is intended as a question about integral factors, those that can be paired with another integer to produce the number as a product. In that sense, 9 is not an integral factor of 11, because the paired number with 9 is 11/9, a number that is not an integer.
8
(147,1)(49,3)(21,7)
In the absence of a specific number, 8, 9, 10 and 11 can all be factors. In fact, they're all factors of 3960.