Question 137490
3x-y=23 or -y=-3x+23 or y=3x-23 (red line)
3x+4y=13 or 4y=-3x+13 or y=-3x/4+13/4 (green line)

{{{ graph( 300, 200, -6, 15, -20, 10, 3x -23, -3x/4 +13/4) }}} (graph 300x200 pixels, x from -6 to 15, y from -20 to 10, of TWO functions 3x -23 and -3x/4 +13/4).