How do I graph this?

Isolate y first:

3x+y<-6

y < - 3x - 6

The solution set is a portion of the plane.

Draw the line, y = - 3x - 6 with a dotted line since it is a strict inequality (no EQUALS part)

Then you can either use a test point on one side of the line to see if it makes a true inequality OR:

The inequality SAYS y-values that are less than the y-values on the line. WHERE is that ??

It's BELOW the line. Shade that part of the plane.

Since there is no = sign with the inequality sign, you will have a dotted line on your graph.

Change the basic formula into the form of : y = mx + b.

Then graph that line with a dotted line.

Then check points on both sides of the line. Whichever point is true, you will shade that side of the dotted line.