Answer:
I'm not sure if i'm correct but, I believe it's no solution. Start with distributive property so 7 times x and 7 times -4. You'll get 7x-28 on the right side of the equal sign. Then if go to the left side you have two x variables so let's add those together. That will give us 7x -12 on the left side of the equal sign. From here your supposed to minus one of the x variables to the other sides but since there both 7 they will cancel each other out. From there you'll be left with -12 = -28 which is an untrue statement so no solution.
Explanation: