I want to know how to do #18 on the multiple choice section.
First of all, what is the domain of this function (i.e., the values of for which it is defined)? Answering that alone should give you the answer.
If you want to look at it another way, think about what the square root function looks like. What happens to its graph when you start to add constant values under the radicand?
1. Find the domain of the function
2. Find the range of the function
3. Find the x- and y-intercepts of the function
4. (If you know calculus) Determine on which intervals the function is increasing/decreasing, determine concavity, find extrema and inflection points
5. See which graph best matches the gathered information, or if you need to draw the graph, plot the intercepts and a few points on the curve and connect them smoothly
What more do you want, short of a full solution?