We are going to use the equation y = mx + b
m is the slope
and b is the y intercept
Let's do b first because it is the easiest.
Y intercept is where ever the line touches the y axis
If you look at the graph, you can see easily that the y intercept is -4
Let's find the slope now
We are going to use points we can clearly see on the graph
In this case we are going to use (-4,-1) and (0, -4)
To find slope we do
Lets plug it in. { -4 - -1 } = -3
and for x2 - x1, it would be 0 - -4 = 4
so your slope is
Let's put everything all together.
The final equation is
Hope I helped, message me if you have questions :)