PSAT Math Multiple-Choice Question 489: Answer and Explanation

Question: 489

The xy-plane above shows a graph of the line y = tx – r, where t and r are constants. What is the value of r?

• A. –8
• B. –4
• C. 4
• D. 8

Correct Answer: C

Explanation:

C

The question asks for the value of r in the provided equation y = tx – r. The graph shows that the line crosses the y-axis at the point (0, –4), meaning that the line contains this point. Plug the coordinates of the point, x = 0 and y = –4, into the equation to get (–4) = t(0) – r. This simplifies to –4 = –r, so 4 = r. The correct answer is (C).