Making a variable a subject is basically isolating it on one side. So in this case to make "x" a subject, we are just trying to get it alone on one side. You are solving for x.
1. Write the problem-----> 4x+c=w
2. Subtract "c" from both sides ------> 4x=w-c
3. Divide by 4 on both sides. You would need to divide (w-c) by 4 because the 4 has to apply to both variables!---------------> x=(w-c)/4
