parallel
If you mean y = 2x and y = 2x-1 then they are parallel lines because they have the same slope.
They are parallel lines
They are parallel lines with a vertical separation of 1.
If you mean: y = 2x and 2y = -x+4 then they are positive and negative straight line equations
They are parallel lines.
They are parallel lines.
They are straight lines.
neither
If: 12 = 2y+x then y = -1/2x+6 So: y = 2x+4 and y = -1/2x+6 which means that they are perpendicular lines
parallel
The lines are parallel, but not the same.
y2x is an expression, which cannot be graphed because we don't know what it equals. y = 2x, y2 = x, and 2y (or y2) = x are all things that could actually be graphed.