You can put this solution on YOUR website! 2x-y=4, -y=-2x+4, y=2x-4 (red line)
4x-2y=-8, -2y=-4x-8, y=(-4x/-2)-(8/-2), y=2x+4 (green line) (graph 300x200 pixels, x from -6 to 5, y from -10 to 10, of TWO functions y = 2x -4 and y = 2x +4).
According to the graphing --- there is no common solution.