How do you graph a linear equation with two variables? y= -3x-4

First, lets break up the equation into pieces.

The first variable is slope, in your case here, we have a slope of -3 or -3/1.

The other variable is the y-intercept, which is where place on the graph where you plot (0,X), in your case here we got (0,-4). That is the y-intercept.

to graph it you have to plot the y-intercept, and then identify the slope.

Here is an example.