Answer:
see below.
Explanation:
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.