SAT Math Multiple Choice Question 480: Answer and Explanation

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Test Information

Question: 480

15. If the equation has solutions x1 and x2, what is the product of x1 and x2?

  • A. –45
  • B. –15
  • C. –5
  • D. 3

Correct Answer: A

Explanation:

A

Difficulty: Hard

Category: Passport to Advanced Math / Quadratics

Strategic Advice: This is a quadratic equation, so you need one side to equal 0 and then, best-case scenario, you'll be able to factor. If not, you can rely on the quadratic formula.

Getting to the Answer: First, subtract 3 from both sides of the equation. Then multiply everything by 9 to clear the fractions.

Each number in the equation is divisible by 2, so factor out a 2 and go from there.

The solutions are –15 and 3, but be careful! The question asks for the product of the solutions, so the correct answer is (–15)(3) = –45.

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