Open Middle: Equations of Parallel Lines

Creation of this resource was inspired by an Open Middle problem from Bryan Anderson.

Using the digits 1 to 9 at most one time each, fill in the blanks (at the bottom) to create two distinct parallel lines. Explore!

How do you know the equation of your lines are parallel? Explain as best as you can.

Same exercise as above: This time create a different pair of parallel lines using non repeating digits ranging 1 to 9.

Given the constraints of this problem, try to create another pair of parallel lines so each one has a SLOPE that is as LOW AS POSSIBLE.

What is the value of this lowest possible slope? What prevented you from getting a lower value?

Given the constraints of this problem, try to create another pair of parallel lines so each one has a SLOPE that is as HIGH AS POSSIBLE

What is the value of this highest possible slope? What prevented you from getting a higher value?