Question 67589
x+y=4
y=-x+4
{{{ graph( 300, 200, -6, 5, -10, 10, y = -x +4) }}} (graph 300x200 pixels, x from -6 to 5, y from -10 to 10, y = 2x +4). 
y=2x-3
{{{ graph( 300, 200, -6, 5, -10, 10, y = 2x -3) }}} (graph 300x200 pixels, x from -6 to 5, y from -10 to 10, y = 2x -3).
y=2-2x2=2. I believe you have a mistake in this equation. Too many = signs.