PSAT Math Multiple-Choice Question 352: Answer and Explanation

Question: 352

If (x, y) is a solution to the system of equations shown above, then what is the value of x - y ?

• A.
• B.
• C.
• D.

Correct Answer: D

Explanation:

D

Difficulty: Medium

Category: Substitution

Getting to the Answer: Because x has a coefficient of 1 in the second equation, solve the system using substitution. First, solve the second equation for x to get x = 6y + 10. Then, substitute the resulting expression for x into the first equation and solve for y:

Next, substitute this value back into x = 6y + 10 and simplify:

Finally, subtract x - y to find that (D) is correct: