From the graph, we can see the line is passing through the points (-3,0) and (0,-3).
So the x-intercept of the graph is -3 and y-intercept of the graph is -3.
The slope of the line passing through (-3,0) and (0,-3) is
Hence slope of the line is m= - 1.
Now we know that equation of a straight line with slope m and intercept c is
Hence the equation is