Parallel lines are non vertical lines that have same the same slope but different Y-intercepts. The way to now if two lines are parallel is if they both never touch and are both on the y-axis having the same slope.
This picture shows they both have a slope of one and never
touch so they are parallel.
Perpendicular is when two lines intercept. The product of perpendicular lines is their slopes are (-1). A vertical and a horizontal line are perpendicular
