You have two types of numbers here, you have a coefficient, and you have regular numbers. Now do keep in mind that you can never add a regular number to a coefficient. So the only thing in this problem you will add is 3 and 2. Because 3x is different
Every time the number is divided by 2 like 8 divided by 2 is 4 and 4 divided by 2 is 2 and so on so if you divide 1/4 by 2 it would be 0.125 and that in fraction would be 1/8.