how do you find the slope of two parallel lines?

Question

line a: (-5,2), (-4,-1)

line b: (-2,1), (-1,-2)

Answer 1

So, the slopes of parallel lines are the same, but with different y-intercepts. How fo we find slope? Change in y/change in x. You can go either direction, as long as you go the same direction.

 

(-1 - 2)/(-4 -(-5)) = -3/1 = -3

 

Or...

 

(2 - (-1))/(-5 - (-4)) = 3/-1 = -3

 

Line b gives the same result.