SAT Math Multiple Choice Question 797: Answer and Explanation
The graph of a system of linear equations is shown above. If the ordered pair (x, y) represents the solution to this system, what is the value of x – y?
- A. –4
- B. –2
- C. 2
- D. 4
Correct Answer: D
Category: Heart of Algebra / Systems of Linear Equations
Strategic Advice: Don't overthink a question like this. You do not need to write the equations of the lines. The solution to a system of linear equations represented graphically is the point of intersection, which you can clearly see on the graph.
Getting to the Answer: According to the graph, the lines intersect, or cross each other, at (3, -1). The question asks for the value of x - y, so subtract to arrive at the answer 3 - (-1) = 3 + 1 = 4, which is (D).