-9 would be the y intercept and 5/3 is the slope/gradient.
The y intercept shows there should be a point at (0, -9) on the y axis.
From that point you can use the slope and go up 5 and over to the right 3 before plotting the next point. You can keep doing that in that direction and you can also go in the reverse by going down 5 and to the left 3 if necessary in the graph.
In the end it would look like this.
