Hi!
So the first thing to do is to combine the common terms on each side.
On the left side, 13 and 2a cannot be put together because 2 has a multiplier that 13 does not.
On the right side, however, there are two numbers with the multiplier a. Add those together!
3a + 2a = 5a.
13 + 2a = 5a - 14
Now we want to isolate a to one side. Let's do the right side.
To do this, we have to subract 2a from both sides to get a on only one side.
13 + 2a - 2a = 5a - 2a - 14.
Subract.
13 = 3a - 14.
We have to do the same for the 14 on the right side. Instead, since the number is being subracted from 3a, we have to add it to both sides.
13 + 14 = 3a + 14 - 14.
27 = 3a
a = 9.
