Question 205140
9y-6x=12
9y=6x+12
y=6x/9+12/9
y=2x/3+4/3 (red line)
6x-9y=-12
-9y=-6x-12
9y=6x+12
y=6x/9+12/9
y=2x/3+4/3 (green line)
{{{ graph( 300, 200, -6, 5, -10, 10, 2x/3 +4/3, 2x/3 +4/3) }}} (graph 300x200 pixels, x from -6 to 5, y from -10 to 10, of TWO functions 2x/3 +4/3 and 2x/3 +4/3). 
As you can see these 2 lines (equations) are identical with many solutions for both x & y.
One set is (-2,0) & (0,4/3)