Question 8341
Slope of a Line:
If a line passes through two distinct points P1(x1 , y1) and P2(x2, y2), its slope is given by: 
m = (y2 - y1) / (x2 - x1) 
with x2 not equal to x1. 

There are two basic forms of a line, the point-slope and the standard
(the standard is sometimes also called the slope-intercept form).  
They are:

Standard: y = mx+b  
          m is the slope
          b is the y-intercept (the value of y when x=0)

Point-Slope: (y-y1) = m(x-x1)    
             m is the slope  
             (x1,y1) is the given point (some point on the line)

Given points (x1,y1) and (x2,y2) find the equation of the line.
  
  1) get the slope by m = (y2-y1)/(x2-x1).
  2) pick either (x1,y1) or (x2,y2) as the point to use with your 
     slope.
  3) substitute values into the equation (y-y1) = m(x-x1)
thatz all!