What is the equation of the line that passes through (-6,-6) and (12,9)?

The correct answer for the question that is being presented above is this one: 

(1) Get the slope (m)
m = (y1 - y2) / (x1 - x2)
m = (-6 - 9) / (-6 - 12)
m = -15 / -18
m = 5/6

(2) Get the x-intercept (b)
y = mx + b
-6 = (5/6)(-6) + b
-6 = -5 + b
b = -1

(3) Form the equation
y = mx + b
y = (5/6)x -1

So the equation is y = (5/6) x - 1.