Slope y-Intercept Form

y = mx + b
m is slope and b is y-intercept.

ex) Write the slope y-intercept form for the points (-2, 1) and (4, 4).

First find slope
= (y2 - y1)/(x2 - x1)
= (4 - 1)/(4 - (-2))
= 3/6
= 0.5 or 1/2

Now that we have a y-coordinate, the slope and an x-coordinate we can find the y-intercept.
b = y - mx
b = 4 - .5(4)
b = 4 - 2
b = 2

y = 0.5x + 2

http://www.gomath.com/exercises/SlopeEquationYintercept.php
http://www.learningwave.com/lwonline/algebra_section2/yintercept2.html
http://en.wikipedia.org/wiki/Linear_equation