I believe the greatest common factor would be 1 because there are no other multiples that are the same. 1•21=21, and1•40=40
It is graph b, its negative
Answer: 3n-1
The difference between each of the numbers is 3. This means that we have 3n.
If we assume that for the first number n=1, then 3*1=3, but the value we have is 2. This means that we must subtract 1 to get from 3 to 2.
You have to add all the common terms together.