Parallel Lines and Slope: Open Middle

Below, mathematically justify how and why you know your lines (above) are parallel. Explain.
Try to create another pair of parallel lines different from the ones you created before.
Below, mathematically justify how and why you know your lines (above) are parallel. Explain.
What is the GREATEST POSSIBLE VALUE you can make the slopes of both lines so these lines are parallel and so no digit repeats? Create a setup here!
What is the LEAST POSSIBLE VALUE you can make the slopes of both lines so these lines are parallel and so no digit repeats? Create a setup here!
– Tim Brzezinski

Information: Parallel Lines and Slope: Open Middle