SAT Math Multiple Choice Question 942: Answer and Explanation

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Question: 942

10. Which of the following are zeros of the quadratic equation? (Note:)

  • A.
  • B.
  • C.
  • D.

Correct Answer: B

Explanation:

B

Difficulty: Easy

Category: Additional Topics in Math / Imaginary Numbers

Strategic Advice: The zeros of an equation are the same as its solutions. Take a peek at the answers. The i's in some of the choices are a clue that solving by factoring may not be possible for an equation like this.

Getting to the Answer: Don't be tempted to use a factoring shortcut here-this is not a difference of two squares. The left side of the equation is a sum of two squares, so you cannot factor it. Instead, subtract 9 from both sides of the equation and use square rooting. Keep in mind that:

This means (B) is correct.

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