Check the picture below.
the line you drew for y = 2x +3 is correct, now recall that the line for x = 3 is just a vertical line, in red, and that y = 2 is just a horizontal line, in green.
now all lines are solid because all are using ⩽ or ⩾, meaning the borderline is included, and you can do a "true" "false" region check if you wish, but less than 3 is to the left of the red one, greater than 2 is above the green one and less than 2x + 3 is just to its left.
