First step:
Get k by itself!
The opposite of adding is subtracting so u need to subtract 4 from both sides in order to get k by itself
K + 4 = 7
- 4 - 4
Second step:
Since 4 - 4 = 0, it cancels out. Now k is by itself and now you need to subtract 7 by 4
7 - 4 = 3
Answer:
K = 3