The slope intercept form would be y= 1/3x -3
First, you add 3y to each side
That cancels out the -3y on the left side of the equation and adds a +3y to the right
Now you have x = 3y + 9
Subtract 9 from each side and now you have
3y = x - 9
Now all you have to do is divide 3 from each side
3y divided by 3 = y
x divided by 3 = x/3 or 1/3 x
-9 divided by 3 = -3
The end result is y = 1/3x - 3