Question 1066832
y=-3 is a horizontal line along the line y=-3. The slope is 0.
3x+y=6
y=-3x+6
This is a line with intercept 6, so the point (0,6) is on it. The slope is -3 so that is down 3 and to the right 1 or to  the left 1 and up 3.  It slopes steeply down to the right because it is large negative.
put in 1 for x and -3+6=3 for y: (-1,3) is a point.
You can go to the original 3x+y=6 and get 2 points: Let x=0 and y=6.  Let y=0 and x=2.  The points are (0,6) and (2,0).  That is because when x=0 the equation is y=6 and when y=0 the equation is 3x=6.
{{{graph(300,300,-10,10,-10,10,-3x+6,-3)}}}