The points P and Q are on the graph of:
y^2-xy+8=0
have the same x-coordinate x=6. Find the points of intersection of the tangents to the graph at P and Q.
assuming I did it right I got (6,-4)(6,-2) for the coordinates. But I can't seem to get the right answer. when I derived I got -y/(x-2y) upon inserting the y's in I get coordinates that aren't in my answer choices. unless there is something else I need to do... Help please.

Question

The points P and Q are on the graph of: 
y^2-xy+8=0
have the same x-coordinate x=6. Find the points of intersection of the tangents to the graph at P and Q. 
assuming I did it right I got (6,-4)(6,-2) for the coordinates. But I can't seem to get the right answer. when I derived I got -y/(x-2y) upon inserting the y's in I get coordinates that aren't in my answer choices. unless there is something else I need to do... Help please.