Hello, I will try my best to explain this to you as simple as possible.
First, you have to pass the -4 to the other side, like this:
-3 1/2x - 4 = -38 1/8
↓
-3 1/2x = -38 1/8 - 4
Then, you have to subtract -4 from -38 1/8, like so:
-3 1/2x = -38 1/8 - 4
↓
-3 1/2x = -42 1/8
My preferred method for this next step is this:
-3 1/2x = -42 1/8
↓
-7/2x = 337/8
Then, we divide:
-7/2x = -42 1/8
↓
x = (-337/8) / (-7/2)
x = 12.0357142857
So, the answer is: 12.0357142857.
Hope this helped! c: