Given the equation y = -2x-5, is of the form y =mx+c, which is the general equation of a line. So, y = -2x-5 is a straight line.
The straight line passes through the points (-2, -1), (0,-5) and (2, -9).
To graph, the straight line, plot the three points on the graph and join the points with a straight line, which will be the desired graph.