SAT Math Multiple Choice Question 409: Answer and Explanation

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Test Information

Question: 409

4.

If (x, y) is a solution to the system of equations above, what is the value of x2?

  • A. 12
  • B. 20
  • C. 60
  • D. 144

Correct Answer: A

Explanation:

A

Difficulty: Medium

Category: Passport to Advanced Math / Quadratics

Strategic Advice: Even though one of the equations in this system isn't linear, you can still solve the system using substitution.

Getting to the Answer: You already know that y is equal to 3x, so substitute 3x for y in the second equation. Don't forget that when you square 3x, you must square both the coefficient and the variable.

The question asks for the value of x2, not x, so there is no need to take the square root of 12 to find the value of x. The answer is (A).

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