Thank you for the opportunity to help you with your question!
I assume that the first line is actually y = x + 7. If not, then you don't have a SYSTEM of linear equations.
First off, if y = x+7 and y = 9-x, then (since y = y)
x + 7 = 9 - x. Adding x to both sides yields 2*x + 7 = 9. Subtracting 7 from both sides yields 2x = 2, so x = 1. Since x = 1 is not one of the available values, this means that one or the other (or both) of the two equations is misstated.
Let's try assuming that y - x = 7. Adding x to both sides yields y = 7 + x. So if y = y, then 7 + x = 9 - x and so
adding x to both sides yields 7 + 2x = 9, and 2x = 2, as before.
You need to check the expressions in column 1. Let me know what you discover and we can solve the problem.
Please let me know if you need any clarification. I'm always happy to answer your questions.