The equation of the line is y = 2x - 4 or 0 = 2x - y - 4
everything in the yellow area (including the line itself)
would be less than this line
2x - y - 4 >=0 a,b and c are integers and have no common factor greater than 1
Here is a graph:
https://www.desmos.com/calculator/cq8gtx2vek