4k - 3 = 2k + 5
+ 3 + 3
-------------------------
4k = 2k + 8
-2k - 2k
-------------------------
2k = 8
------ -----
2 2
k = 4
You can also do it this way:
4k - 3 = 2k + 5
- 4k - 4k
------------------------
-3 = -2k + 5
-5 - 5
------------------------
-8 = -2k
----- ------
-2 -2
4 = k
As you can see, you will get the same answer either way you figure it out :)
