X and Y both represent the position on a graph. So, to find the X- or Y- intercepts, simply set the other value to zero. (After all, the x-intercept is when y is zero, and vice versa.)
So for X...
2/3x-1/3(0)=2
2/3x=2
/(2/3)
x=3
So the X-intercept is at (3,0).
Now, the y-intercept.
2/3(0)-1/3y=2
-1/3y=2
/(-1/3)
y=-6
So the Y-intercept is at (0,-6).