First find the slope between any two points:
Where
are the two points
So calculating the slope:
So the slope is
And our equation will be in the format of
where
and 
So, now we have half of the equation:
Now to calculate b, we can plug in a point
and solve for b.
So
Lets use the point
So:
And then:
So our final equation is
Where
So calculating the slope:
So the slope is
And our equation will be in the format of
where
So, now we have half of the equation:
Now to calculate b, we can plug in a point
So
Lets use the point
So:
And then:
So our final equation is