Is the lines parallel?

Question

Determine whether the line through (2,4) and (6,1) is parallel to a second line through (-3,1) and (1,-2).

Answer 1

Two lines are parallel if their slopes are equal. To find the slopes, you take the rise over the run:

 

(4-1)/(2-6) = -3/4

(1-(-2))/(-3-1) = -3/4

 

The slopes are equal, so the lines are parallel.