-3x-y=0

-3x=y

y=-3x+0 where -3 is the slope and 0 is the y-intercept

the slope can be written as -3/1 or 3/(-1) and is the rise/run

start at the origin and move 1 unit to the right and 3 units down to point (1,-3)

from this point again move 1 unit to the right and 3 units down to point (2,-6)

call the slope 3/(-1) this time

from the origin move 3 units up and 1 unit to the left to point (-1,3)

from this point again move 3 units up and 1 unit to the left to point (-2,6)

you now have 5 points including the origin

connect the dots with a ruler and put arrowheads at each endpoint