The graph is shaded <em>above</em> the <em>dashed</em> line, indicating y-values in the solution are greater than those on the line, so your inequality will start with ...
y >
The y-intercept of the line is (0, -3), so the "b" value in ...
y > mx +b
will be -3.
The line has a rise of -3 for a run of 3 (between the marked points), so the slope is ...
Y=5x-3. First, you have to find the slope, which is 10/2 or 5/1. Then, you plug in the x and y with either of the 2 coordinates (I chose the first), and sole for the y-intercept.