@maxdancona,
For question #1 try the following points.
(1,1)
(1,-1)
(-1, -1)
(-1, 1)
x + y = 0
Plugging in the point (1,1), I get 1 + 1 = 0, which is a false statement.
Plugging in the point (1, -1), I get 1 - 1 = 0, which is a true statement.
Plugging in the point (-1, -1), I get -1 - 1 = 0, which is a false statement.
Plugging in the point (-1, 1), I get - 1 + 1 = 0, which is a true statement.
Answer: For x + y = 0, points in the form (x, y) are located in quadrants 2 and 4.