PSAT Math Multiple-Choice Question 428: Answer and Explanation

Question: 428

The graph of the function f(x) is shown above. What is the domain of the function?

• A. y ≥ -4
• B. All real numbers
• C. y > -4
• D. The domain is undefined.

Correct Answer: B

Explanation:

B

Difficulty: Easy

Category: Graphs of Functions

Getting to the Answer: The domain of a function is all possible x-values. In this case, the arrows indicate the graph is going to continue infinitely in both directions, so every x-value is possible, meaning the domain of the function is all real numbers.(B) is correct.

Note that if you forgot whether it is the x- or y-value that gives you the domain, (A) would have been a tempting choice. (A) actually gives the correct range of the function, which is determined by all possible y-values.