I would contact your instructor, because I think there may be a typo in the original problem. I worked it out and got x = -4 The steps go like this:
1. Distribute the 3 to each of 1/3x and 1. This gives you x + 3 + 4 on the left side. Simplify that to x + 7.
2. Distribute the -4 to each of x and 3. This gives you -1 - 4x - 12 on the right side. Simplify that to -13 - 4x. Now you have x + 7 = -13 - 4x.
3. Subtract 7 from both sides.
4. Add 4x to both sides. Now you have 5x = -20 (This is the step Antwon gets to)
5. Divide by 5. You get x = -4
