PSAT Math Multiple-Choice Question 487: Answer and Explanation

Question: 487

A line that contains the point (, 0) is graphed in the xy-plane above. Which of the following equations represents the line?

• A. f(x) = –3x + 2
• B. f(x) = –x – 2
• C. f(x) = –2x + 3
• D. f(x) = –x + 1

Correct Answer: D

Explanation:

D

The question asks for an equation that represents a graph. To find the best equation, compare features of the graph to the answer choices. The graph for this question has a y-intercept of 1 and a negative slope. Eliminate answer choices that do not match this information. All the answers are in y = mx + b form, in which m is the slope and b is the y-intercept. The equations in the answers all have a negative slope, so nothing can be eliminated based on that. Eliminate (A), which has a y-intercept of 2. Choice (B) has a y-intercept of –2, so eliminate (B). Choice (C) has a y-intercept of 3. Eliminate (C). Choice (D) has a y-intercept of 1, which matches the graph. The correct answer is (D).