To find graph this, you need to understand the equation.
The formula is y=mx+b, m being slope and b being y-intercept.
We start out graphing by finding where the y-intercept is--and we see that our intercept is 2. Place a point on (0, 2).
Now, we need to add our slope. Start at (0, 2) and go up 4 units. Next go to the LEFT (we have a negative slope, remember?). Continue this pattern.
It should look like this once it's done: