We have to calculate the slope and the y-intercept.
The y-intercept can be seen directly in the graph at y(0)=-1.
To calculate the slope, we find another point in the line. For example the point (-4,4), that we are sure it belongs to the line.
We can calculate the slope as:
The slope is m=-5/4.
The y-intercept is b=-1.
The equation of the line is y=-(5/4)*x-1