PSAT Math Multiple-Choice Question 187: Answer and Explanation

Question: 187

If the equation of the line shown in the figure above is written in the form , which of the following could be the value of m ?

• A. - 3
• B.
• C.
• D. 3

Correct Answer: C

Explanation:

C

Difficulty: Medium

Category: Heart of Algebra/Linear Equations

Getting to the Answer: The slope-intercept form of a line is y = mx + b. In this question, the graph passes through the origin, so b is 0. Because b is 0, the equation of this line in slope-intercept form is y = mx, which can be rewritten as . Count the rise and the run from the origin, (0, 0), to the next point, (3, 1), to get a slope of . This matches (C).