To graph y=-3x-4, you need to graph the first point, which would be (0,-4). I know this because of the -4 part in the equation, which represents where the line intersects the y axis.
Then, to find the other points, you have to realize that -3x is the slope of the line.
The slope can also be written as rise/run. Negative 3 is basically -3/1.
So, to find the next point, go down three units from (0,-4) and then one to the right.
Repeat this a few more times.
To get the points that are on the left side of the y axis, go back one and up three from (0,-4). Repeat again.
When you're done, connect all of the points and label the line y=-3x-4.
Do the exact same thing with the next part. If you need me to explain that, too, I'd be glad to.