Alright, first we take our points and subtract them.
(6,12)
-(-2,-8)
(8,20)
Then we reduce this by Rise (y) over Run (x)
20/8 = 2 1/2
Then we take our equation y = mx + b
M = Slope which we just solved for.
Now we take one of our points, to solve for B
y = mx + b
-8 = 2 1/2(-2) + b
Now just solve for B
-8 = -5 + b
-3 = b
Now our full equation, is y = 2 1/2x - 3. Hope this helped!
-TTL