If you need to show work for it I can help with that. First to get rid of the -4, you add 4 on each side (what you do to one side, you must do to the other as well) that will give you 20=4x. Next to get x by itself, we divide both sides by 4 (you divide by the number next to x). 20 divided by 4 is 5. So x=5
