[MOVED] Expression Tables

I'm trying to help my middle school (6th grade) son with his math and I am stumped.

The problem states:

"Find an expression for each table."
The missing number is below the "x".

I've searched high and low for guidance on how to solve the problem. Any help you can give us would be very appreciated!

Thanks!

Trying to work through a "translator" who doesn't understand the content is, unfortunately, almost never successful. Please have your son reply (or dictate a reply), stating the techniques he has learned and what he has tried.

For instance, does he know how to plot points? Find line equations? If so, how far has he gotten with that? If not, what method was he taught? (There are many different ways of going about this, and it would probably be best to stick with whatever he's supposed to be using, is why I ask.)

Thank you.

Eliz.