Term 3
Common difference 12
That means that you add 12 to the term, over and over again
3, 3 + 12, (3 + 12) +12, ...
That is 3, 15, 27, 39....
Term 5
Common difference 1,3
Same way, we add 1,3 to the term
5, 5 + 1,3, ....
That is 5 , 6,3 , 7,6 , 8,9 .....