Question 85023
3x + y = –1  [re-write in the slope-intercept format (y=mx+b)]
3x -3x +y=-1 -3x
y=-3x-1
and
9x + 3y = –3 [re-write in the slope-intercept format (y=mx+b)]
9x-9x+3y=-9x-3
3y=-9x-3
3y/3=-9x/3- 3/3
y=-3x-1

.
Graph both equations.  Since both equations are the same, they are the same line and will show up on the graph as a single line.  The y-intercept will be (0, -1).  The x-intercept will be (-1/3, 0) and the slope will be (-3/1) and 3/-1).

{{{ graph( 300, 200, -4, 5, -4, 10, -3x-1 ) }}}