Plot #(1,2)# on a graph then use the slope to find other points, then connect the dots with a ruler or other straightedge.

Explanation:

We can first plot the point #(1,2)# on a graph then use the definition of slope or "rise over run" to draw more points. Since the #m=-3#, we know that each time we move right #1# unit, we need to move down #3# units. So, our graph should look like this. graph{y-2=-3(x-1) [-10.17, 9.83, -2.84, 7.16]}