Answer:
Add a point at (-1,2) and (0,-1), then connect them
Step-by-step explanation:
The y-intercept is -1 so automatically, you know that (0,-1) is a point. Then since the slope is -3x, one of the points it comes across is (-1,2). Next just connect these lines and make them go further to each side and you're done.
P.S i suggest using a site called desmos if you ever need help with graphing anything ;)