Start off with the y-intercept which is (0,-45) since your b in y=mxtb is -45. Since your slope is 5, your next point would be (1,-40) if towards the right or (-1,-50) if towards the left. The slope is rise over run and 5 is 5 over 1. If towards the right the next point would be 5 units up and 1 units to the right from the previous point. If to the left, you reverse the process.