PSAT Math Multiple-Choice Question 147: Answer and Explanation

Question: 147

When the equation y = 2x - b, where b is a constant, is graphed in the xy-plane, the line passes through the point (3, -1). What is the value of b?

• A. -5
• B. -3
• C. 1
• D. 7

Correct Answer: D

Explanation:

D

The question asks for the value of b in the equation when graphed and provides a point on the graph. Plug the point into the equation. Plug x = 3 and y = -1 into y = 2x - b to get -1 = 2(3) - b. Simplify the right side to get -1 = 6 - b. Subtract 6 to both sides to get -7 = -b. Divide both sides by -1 to get b = 7. The correct answer is (D).