You graph this equation by first graphing the y-intercept, which is -8, according to your equation.
You will plot down, (0,-8) on your graph as your first point. Then since the slope is -3, you will go from that point (0, -8) 3 down and 1 right. So your next point would be (1, -11) and go 3 down and 1 right again for your third point, and keep going if you want more points.
After graphing as many points as you want graph a line though it! It has to be a straight line.
Hope this helps!! :)
