7x-y=14, solve for x:
When solving for x, you are trying to isolate the x variable, so first, add y to both sides.
7x=14+y
Now, divide both sides by 7.
x=14/7+y/7
x=2+y/7
You can also change y/7 to 1/7y.
That's the most you can solve for x without given any other information.
Hope this helps :)