Summary of Formulas
   

 

Slope

Midpoint

Distance
   
   
   

Parallel
(use ||  for “is parallel to”)
If two lines are parallel, their slopes are equal..
 
 
Perpendicular
(use  for “is perpendicular to”)
If two lines are perpendicular their slopes are negative reciprocals.
The product of the slopes is -1
   
   

Equation of a Line
 

Slope Intercept Form

If m = slope and b = y-intercept then the equation is
 
 

Point Slope Form

If (x1, y1) is a point on the line and m = slope then the equation is