Now, once I solve that equation, I'll have a VALUE, a number, for x. That's my x for my solution.
Now I just need y. Well, I have two equations, and again - remember what this solution must be: an (x,y) pair that satisfies BOTH equations. So NOW I'm going to take that x I just found, and plug it into either equation, and solve for y.
Check the solution (plug both x and y into both equations, and they should be true). After you confirm that it works, THAT is your solution to the system.