To help with this problem, I have created a graph with these two lines with the slope and it will help you understand parallel lines.
To most students, parallel lines are lines that never cross each other.
In this problem however, it's important to think
about parallel lines in a different way.
Notice that the 2 parallel lines that I have
drawn have the same slope of 2/3.
As a rule, parallel lines will always have the same slope.
So if these lines are parallel,
they each have a slope of 2/3.
Check out the image I have made for you below.