Question 42839
If two points have equal abscissae then they lie on a straight line parallel to the y-axis.
Their abscissa determines how far the straight line is from the y-axis.
If their abscissae are positive [say points A (4,6) and B (4,-8)] then the straight line lies on the right side of y-axis and at a distance equal to the common abscissa (here 4).
However, if their abscissae are negative [say points C (-4,6) and D (-4,-8)] then the straight line lies on the left side of y-axis and at a distance equal to the magnitude of the common abscissae (here 4; as magnitude of (-4) is 4; irrespective of sign]).


If two points have equal ordinates then they lie on a straight line parallel to the x-axis.
Their ordinate determines how far the straight line is from the x-axis.
If their ordinates are positive [say points E (9,6) and F (5,6)] then the straight line lies above the x-axis and at a distance equal to the common ordinate (here 6).
However, if their ordinates are negative [say points G (9,-6) and H (5,-6)] then the straight line lies below the x-axis and at a distance equal to the magnitude of the common ordinate (here 6; as magnitude of (-6) is 6; irrespective of sign]).


See the graph.


{{{drawing(400,400,-10,10,-10,10,
grid(1),
line(4,10,4,-10),
line(-4,10,-4,-10),
line(-10,6,10,6),
line(10,-6,-10,-6),
locate(4,6,A),
locate(4,-8,B),
locate(-4,6,C),
locate(-4,-8,D),
locate(9,6,E),
locate(5,6,F),
locate(9,-6,G),
locate(5,-6,H)
)}}}