I'm not 100% positive but I believe it would be the 14th person. 10+4=14. That's just my guess.
It is a parallelogram!
Also you haven't really put any other info...
The given equation is

x intercept
To find the x intercept, we have to plug 0 for y and solve for x.That is

So x intercept is (6,0) .
y intercept
To find the y intercept , we have to plug 0 for x and solve for y. That is

So the y intercept is (0,-9) .
Could you past the graphs. I would like to help:)