If the sum of 4 and x is greater than 6, we can translate that to x + 4 > 6. To line graph that, it's an open circle at 6 to the +x direction.
EDIT: Sorry, I have a cold and I'm not thinking straight! Since it's x + 4 > 6, subtracting 4 from both sides gives us x > 2. So the open circle starts at 2 and goes in the +x direction.
