(x,y)
x means how many units right from the center the points is (if it is to the left of center, say it is negative units)
y means how many units up from center the point is (if it is under center, say it is negative)
it is to th eleft and above center
(-,+)
count how far to the right
-1.5 units to right
how far up
3 unit sup
(-1.5,3)