PSAT Math Multiple-Choice Question 318: Answer and Explanation

Question: 318

Line m is parallel to line k and passes through (5, 5). The slope of line k is and line k passes through the origin. Which of the following is the equation for line m?

• A.
• B.
• C.
• D.

Correct Answer: D

Explanation:

D

Difficulty: Medium

Category: Linear Graphs

Getting to the Answer: This question provides an equation for a line parallel to line m and a coordinate point for line m, (5, 5). The slope of the parallel line, which is , is the same as the slope of line m. Eliminate (B) and (C) because they have the incorrect slope.

Plug the values for the slope and the coordinate point (5, 5) into the slope-intercept equation to solve for b:

Eliminate (A) because it does not have the correct y-intercept. Only (D) is left and is correct. To confirm, plug the values for the slope and the y-intercept into the slope-intercept equation to get .