It's a straight line (as y = -x +14) so the co-ordinates would be any point that sits on the line eg when x + y = 14 so (1,13) (2,12) (6,8) etc there are an infinite number. Is there not more to the question?
As prudie says, this is the equation of a straight line and you only need 2 points on the line to draw it:
when x=0, y=-14
when y=0, x=-14
Draw a line joining these two points (0,14) and (-14,0) and extend it as far as you like.
Then if you choose a value for x you can read off the corresponding value for y and vice versa.
Also in the form y=mx +c, m is the gradient and c where it cuts the y axis so this particular line is a 45 degree line going downwards from left to right (gradient of -1) and goes through the y axis at 14. ta da :-)