Sorry for not answering till now! But since the first one you meant 7x it makes sense now!
You just have to look at each answer and see what it does for you. Subtracting 5 from both sides doesn't help you. Adding x to both sides doesn't help you. And there are no like terms to combine in the condition the equation is in.
Now if you add 7x to both sides though, it helps you. :)
Hope that helps! Feel free to ask me if you have any questions! :3
