Question

Which graph represents the solution set for the inequality x ≤ 18?

Answer 1

You didn't include any graphs but what you're looking for is a solid vertical line on x = 18 or the ordered pair (18, 0) where the whole left side of the line is shaded. 

EDIT: I said whole left side of the graph; changed it to "line"

Answer 2

Answer:

The answer is D