You need to transform the equation into y = mx + b form. To do this, subtract 8x from both sides to get 3y = -8x + 24. Then divide both sides by 3 to get y = -8/3x + 8. When you graph this equation, the y-intercept will be at (0,8) and it will have a slope of -8/3 (move down 8 and right 3).
Hope this helps!!