When starting with the equation 6x + 3y = 12 the goal is to isolate the y variable on the left side of the equation and fill in y = mx + b
First you subtract 6x from each side:
3y = 12 - 6x
Then isolate y by dividing both sides by 3:
y = -2x + 4 where m = -2 and b = 4
B is the y value where the line crosses the y intercept thus, one of the most obvious points that lie on the line would be (0,4).
Since the slope is also -2 (m = -2), for every time y decreases by 2, x moves over to the right by one, so another point could be (2,0)