For a system of equation to not have a solution, the pair of lines will never intersect. For two lines to never intersect, their slopes will be parallel.
The second equation can be as simple as y = -3x.
The only equation it cannot be with a slope of -3 is y = -3x + 2. This is because that is the same equation and will therefore have an infinite number of solutions.
Right angles will be formed because in drawing the perpendicular lines they all form right angles to begin with. With several more draw it will still be the same as if you are drawing one
