When n=8 and y2=4x/3+8,

Because A is on the X axis, y2, the ordinate of point A is 0, that is, y2=0 in y2=4x/3+8, and y2=0 is substituted into y2=4x/3+8.

-8=4x/3

x=-6

So the coordinate of point A is (-6,0).