The graphical representation of x – y ≤ 3 is given by blue line in the figure below.

This lines divides x-y plane into two parts .

Select a point (not on the line),which lies on one of the two parts, to determine whether the point satisfies the given inequality or not.

We select the point as (0,0)

It is observed that

Therefore, the solution for the given inequality including the points on the line.

This can be represented as follows,