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`?

Options

A. `-4`
B. `-2`
C. `2`
D. `4`

Answer

D

Explanation

Difficult: Easy
Category: Heart of Algebra/ System 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 graph.
Getting to the Answer: According to the graph, the lines intersect, or cross each other, at `(3, -1)`. The equation asks for the value of x-y, so subtract to arrive at the answer `3-(-1)=3+1=4`, which is (D).